JP6095043B2 - Band lineup device and measuring method thereof - Google Patents

Description

  The present invention relates to a band lineup measuring apparatus, and more particularly to a band lineup measuring apparatus with improved band lineup measurement accuracy. The present invention also relates to a band lineup measurement method, and more particularly to a band lineup measurement method with improved band lineup measurement accuracy.

  Conventionally, the band lineup of substances / materials includes the search for substances that decompose water, the search for high dielectric constant gate insulating films (High-K materials) in next-generation Si integrated circuit (SiULSI) technology, and P-type and N-type organics. It is used as an index for searching for semiconductor materials. In the future, devices that require high-precision control and various materials such as organic substances and oxides will be used in the devices, and therefore, band line-up measurement using various materials with high accuracy is required.

The electronic state of a solid is represented by a band diagram with the vertical axis representing energy and the horizontal axis representing the magnitude of the wave vector. For example, FIG. 1 is a simplified representation of a band diagram. Important parameters in the electronic state is a valence band maximum _{E VBM} the conduction band minimum _{E CBM.} The valence band upper end E _VBM is the energy of the uppermost part of the valence band (hereinafter referred to as VBM) corresponding to the highest occupied orbital (HOMO) in the case of a molecule. The conduction band lower end E _CBM is the energy of the bottom of the conduction band (hereinafter referred to as CBM) corresponding to the lowest unoccupied orbit (LUMO) in the case of molecules. Further, it is a Fermi level (E _F ) indicating the energy at the boundary between the occupied and unoccupied states of electrons. The energy at which electrons are no longer bound to matter is called the vacuum level (E _vac ), which is defined as the origin of electron energy. E _vac -E _CBM is called electron affinity (χ), and E _vac -E _VBM is called ionization potential (IP). The band lineup corresponds to the positions of E _CBM and E _VBM with reference to E _vac , and the band gap is the difference in energy between E _CBM and E _VBM (Non-patent Document 1).

In the band lineup, it is necessary to determine the positions of E _CBM and E _VBM measured from E _vac . This band lineup can be determined by combining multiple measurements. As one of the measuring methods, there is a method using ultraviolet photoelectron spectroscopy (UPS) and inverse photoelectron spectroscopy (IPES). In this method, the values of E _CBM and E _VBM and a detailed band diagram can be obtained. On the other hand, this measurement method has a problem that the material to be measured is limited due to utilization of the vacuum environment and charging of the sample for the following reasons.
First, the UPS requires an ultraviolet light source and electron spectrometer by He discharge, and IPES requires a low-energy variable electron source and a photodetector, and each requires an operating environment in ultra-high vacuum. Must be in a high vacuum. Therefore, the measurement method cannot measure water-containing organic substances or substances having a high vapor pressure.
Secondly, since the energy reference of the electron spectrometer is shifted due to the charging of the sample during the measurement, the measurement method can measure only a sample having a relatively high conductivity.

There are the following two measurement methods as the measurement target material is extremely wide.
(A) Ionization potential measurement using a photoelectron yield spectrometer (also known as an ionization potential measurement device) (Non-Patent Document 2) for E _VBM measurement,
(B) Measurement of band gap by light reflection, transmission and absorption measurement using a spectrophotometer.
By using the above two measurement methods, E _CBM and E _VBM can be obtained. Since these measurement methods do not require a vacuum environment for the light source and detector, they can be measured in the atmosphere, so that organic substances including water and substances with high vapor pressure can be measured, and they are not easily affected by charging. Since there is no (nonpatent literature 3), it can measure also to a material (insulator) with low electroconductivity, and a measuring object material is remarkably wide.
The ionization potential measuring device is also disclosed in Patent Documents 2 and 4. Patent Document 2 proposes a work function or ionization potential measuring apparatus that measures the work function or ionization potential of a sample by irradiating the sample with ultraviolet light that has been split and measuring the yield of the emitted photoelectrons. Yes. Patent Document 4 proposes an ionization potential measuring device for measuring an ionization potential from a current value obtained by irradiating a sample with ultraviolet light.

  In the ionization potential measurement, an ultraviolet light source is used, and usually a deuterium lamp or a xenon lamp light source is used. The wavelength of light is inversely proportional to the photon energy, and the wavelength of the light (photon energy) applied to the sample is swept, and the value of the current flowing through the sample at that time is measured. Further, the light intensity of the irradiation light is measured in advance or simultaneously and converted to the number of irradiation photons. Here, the value obtained by converting the current value into the number of electrons and dividing by the number of irradiated photons is the photoelectron yield, and the photon energy at the change point is taken as the ionization potential.

  Similarly, in the band gap measurement, a light source in the infrared region to the ultraviolet region is used, and usually a combination of a deuterium lamp and a halogen lamp, or a xenon lamp is used. The wavelength of the light applied to the sample is swept, and the light intensity reflected or transmitted from the sample at that time is measured. In reflection, the photon energy at the inflection point where the reflectance changes, and in transmission, the photon energy absorbed without being transmitted becomes the band gap.

In the material search, as the device material becomes more accurate, the band lineup value with high accuracy is required. In the band lineup measurement using devices developed for different purposes, accurate measurement cannot be performed for the following reasons.
First, the optical characteristics of each measuring device are different. For example, there are problems such as the wavelength range depending on the output and type of the light source lamp, the difference in the light amount, the transmittance, and the characteristic line, the change in the incident light amount due to the arrangement of the optical lens, and the secondary light and stray light due to the characteristics of the spectrometer.
Secondly, different optical devices differ in the manner of installation on a measuring instrument such as whether the shape of the sample or the measurement surface is vertical or horizontal. For this reason, separate devices need to be changed depending on the device, such as placing a sample in a holder or processing the shape, and there is a problem that the measurement work becomes complicated.
Thirdly, in a separate optical apparatus, the same sample is irradiated with high-energy ultraviolet light at least twice. With high-energy ultraviolet light, an organic material that is easily damaged is exposed to a sample state by irradiation. There is a problem that it changes and cannot be measured accurately.

Patent Documents 1 and 3 disclose inventions for overcoming the first problem. For example, Patent Document 1 proposes a spectrometer having a stray light removal function in a dispersion spectrometer that transmits measurement light twice through the spectrometer. Further, Patent Document 3 proposes a spectroscopic analyzer that includes a filter mechanism that can be easily connected to an optical fiber and that can satisfactorily remove stray light.
However, according to Patent Documents 1 and 3, there is a problem that calibration is required for each optical device. The error range of the final value is widened due to the error of each optical device, and the accuracy is lowered. In addition, since they are separate devices, the amount of light and the wavelength accuracy of the spectroscope strongly depend on each optical device, so that there is a problem that it is difficult to match the same conditions with separate optical devices.

Japanese Patent Laid-Open No. 7-55562 Japanese Patent Laid-Open No. 10-267869 JP 2000-131145 A JP 2009-085823 A

Hideo Hosono and Toshio Kamiya: Ceramics 38 (2003) 825. Hisao Ishii, Daisuke Tsunami, Tamotsu Suenaga, Nobuyuki Sato, Yasuo Kimura, Michio Niwano: Surface Science 28 (2007) 264. Yasuo Nakayama, Shinichi Machida, Daisuke Tsunami, Yasuo Kimura, Michio Niwano, Yutaka Noguchi, and Hisao Ishii: Appl. Phys. Lett. 92, 153306 (2008) S. Sakthivel and H.M. Kisch: Angew. Chem. Int. Ed. , 42 (2003) 4908. Hiroaki Takahashi, Jiro Hiraishi, Norihiko Ishii: Spectroscopic Studies 25 (3), 153-165, (1976) Masato Mamiya: Spectroscopic Studies 25 (3), 99-117, (1976)

In the present invention, when a band lineup is obtained by a plurality of devices, the difference between the optical system and the electronic system of each measuring device, which causes the measurement accuracy of the band lineup to be reduced, the difference in the installation mode of the sample, the damage due to the irradiation of the organic material An object of the present invention is to provide a band lineup measuring apparatus and a band lineup measuring method that overcome the above-described problems and improve the measurement accuracy.

In order to achieve the above-described object, the present invention solves the functions necessary for the target band lineup measurement by simultaneously measuring light (light quantity) and electrons (current) in one apparatus. The monochromatic photon energy irradiated to the sample is swept, and the value of the current flowing through the sample at that time, and the light intensity reflected from the sample when the sample is opaque are simultaneously measured. Note that when the sample is a light-transmitting material, the light intensity transmitted through the sample is simultaneously measured, but the light intensity reflected from the sample may be measured together. The ionization potential IP is calculated by the following equation.
IP = E _VAC -E _VBM (i)
The band gap Eg is calculated by the following equation.
Eg = E _CBM -E _VBM (ii)
Therefore, the band lineup of E _VAC , E _VBM , and E _CBM is determined by combining the measurement results of the ionization potential IP and the band gap Eg. Thereby, the measurement accuracy of the band lineup can be improved.

The band lineup apparatus of the present invention includes a light source unit that emits continuous light including at least one of an infrared wavelength, a visible wavelength, and an ultraviolet wavelength, as shown in FIGS. 2, 7, and 8, for example. (1), a spectroscope (4) that extracts light of a specific wavelength from continuous light, a light irradiation unit (5, 9) that irradiates the sample 31 with light of a specific wavelength, and the sample 31 caused by the irradiated light A light quantity measurement unit comprising at least one of a reflected light measurement unit (58) for measuring light reflected from the surface and a transmitted light measurement unit (72) for measuring light transmitted through the sample 31, the light irradiation unit 5 and the sample 31 A collector electrode (21) provided between the current collector, a current measuring unit (2) for measuring the current caused by the irradiation light and flowing between the sample 31 and the collector electrode 21, and a spectrometer A control device (83) for controlling the specific wavelength extracted by 4; Provided, characterized in that it can calculate the light amount measurement unit and the current measuring unit of the measuring results from the basis of the vacuum level of the sample 31 was valence band maximum energy (E _VBM) and conduction band minimum energy (E _CBM). Preferably, the analysis device 82 calculates the valence band upper end energy (E _VBM ) and the conduction band lower end energy (E _CBM ) of the sample 31 from the measurement results of the light amount measurement unit and the current measurement unit, and measures the band lineup. It is good to do.

In the apparatus configured as described above, the light source unit 1 emits continuous light including at least one of an infrared wavelength, a visible light wavelength, and an ultraviolet wavelength. The spectroscope 4 obtains monochromatic light as monochromatic photon energy from the continuous light emitted from the light source unit 1. The light irradiation unit (5, 9) irradiates the sample with the monochromatic light. The reflected light measuring unit 58 measures light reflected from the surface of the sample 31 due to the irradiated light, and is used when the sample 31 is not light transmissive, and also when it is light transmissive. May be used. The transmitted light measurement unit 72 measures light transmitted through the sample 31 and is used when the sample 31 has light transmittance. When the sample 31 is translucent, both the reflected light measurement unit 58 and the transmitted light measurement unit 72 can be used. The current measuring unit 2 measures the current flowing between the sample 31 and the collector electrode 21. The control device 83 controls the specific wavelength taken out by the spectroscope 4, and it is preferable to sequentially change the wavelength for each of the wavelength in the infrared region, the wavelength in the visible light region, and the wavelength in the ultraviolet region. Thereby, the valence band upper end energy (E _VBM ) and the conduction band lower end energy (E _CBM ) of the sample 31 are calculated from the measurement results of the light quantity measurement unit and the current measurement unit, thereby enabling measurement of the band lineup.

  In the band lineup apparatus of the present invention, preferably, the band lineup apparatus further includes a moving mechanism 33 that moves at least one of a vertical direction and a parallel direction with respect to the optical axis of the light that irradiates the sample 31, and the control device 83 moves. The mechanism 33 may be controlled so that the position of the surface of the sample 31 irradiated by the light irradiation unit 59 is controlled. Preferably, a position control device (83) for controlling the position of the surface of the sample 31 irradiated by the light irradiation unit 59 is preferably provided.

  In the band lineup apparatus of the present invention, preferably, further, a sample holder 32 on which the sample 31 is installed, a collector electrode 21 provided between the sample 31 and the light irradiation unit 59, and at least of the sample holder 32 and the collector electrode 21 It is preferable to have a DC voltage source (22, 24) for applying a DC voltage including a ground potential on one side. By adjusting the DC potential of the sample holder 32 and the collector electrode 21, the current (electrons) flowing by the monochromatic light irradiated on the sample can be accurately measured.

  In the band line-up apparatus of the present invention, for example, as shown in FIG. 10 and FIG. 11, the collector electrode 21 is preferably made of metal, and the distance d between the collector electrode 21 and the sample 31 is not measured in atmospheric pressure. When the thickness is 1.0 mm or less, the current (electrons) flowing by the monochromatic light irradiated to the sample can be accurately measured, and noise is reduced. Further, in the measurement at a vacuum or an intermediate pressure between vacuum and atmospheric pressure, the distance d can be appropriately changed based on the distance of the mean free path of molecules determined according to the pressure, and may be several meters in a vacuum, for example.

  In the band lineup apparatus of the present invention, for example, as shown in FIGS. 10 and 11, the collector electrode preferably has a ring shape that does not interfere with the beam diameter of the irradiation light on the optical path of the irradiation light, and the beam diameter of the irradiation light. It is good to be at least one of a short needle shape concerning a part or a mesh shape comparable to the beam diameter of irradiation light.

  In the band lineup apparatus of the present invention, the light source unit 1 preferably has both a halogen light source and a deuterium light source. If comprised in this way, the light source part 1 can radiate | emit continuous light including three types, the wavelength of an infrared region, the wavelength of a visible light region, and the wavelength of an ultraviolet region. Preferably, a xenon light source is used in a complementary manner.

In the band lineup apparatus of the present invention, for example, as shown in FIGS. 2, 7, and 8, the light irradiation unit (5, 9) is preferably configured to irradiate and reflect light from a specific wavelength extracted by the spectrometer 4. It is preferable to have an optical system including a half mirror 52 that separates light, or an optical system including a fiber 9 that divides each of irradiation light and reflected light. If comprised in this way, since a light irradiation part has an optical system containing the half mirror or fiber which divides irradiation light and reflected light, an apparatus is reduced in size.
In the band line-up apparatus of the present invention, preferably, the light irradiation unit (5, 9) further includes an optical system including the half mirror 52 or the fiber 9 that separates the reference light from the light having a specific wavelength extracted by the spectroscope 4. The light quantity measurement unit may include a reference unit (57) that takes out part of the light irradiation and measures it as reference light. With this configuration, since the reference light is obtained from the light having the specific wavelength extracted by the spectroscope 4 from the same optical path as the irradiation light and the reflected light, the conditions for extracting the light having the specific wavelength from the continuous light are substantially the same in terms of time. Therefore, accurate measurement can be performed with little influence from noise.
In the band line-up apparatus of the present invention, the light irradiation unit 5 includes the irradiation light optical fiber 59, and by setting the irradiation light optical fiber 59 to the ground potential, the light irradiation unit 5 can have a function corresponding to the collector electrode. In this case, the collector electrode is also used as an optical fiber for irradiation light.

In the band lineup apparatus of the present invention, preferably, the ionization potential value (IP) and the band gap value (Eg) using the valence band top energy (E _VBM ) and conduction band bottom energy (E _CBM ) of the sample. The band lineup (E _VAC , E _VBM , E _CBM ) may be calculated from the following formulas (i) and (ii).
IP = E _VAC -E _VBM (i)
Eg = E _CBM -E _VBM (ii)

In order to achieve the above object, a band lineup measuring method according to the present invention is a band lineup measuring method using a band lineup apparatus according to claim 1, for example, as shown in FIG. ) To (f).
(A) A step of acquiring a background (dark) spectrum and a reference (ref) spectrum necessary for at least one of reflection measurement and transmission measurement (S302, S304).
(B) A step of applying a DC voltage to at least one of the sample and the collector electrode (S308).
(C) A step of irradiating the sample with monochromatic light having a specific wavelength separated by the spectroscope (S310).
(D) A step of measuring a current value flowing between the collector electrode and the sample when the sample is irradiated with the monochromatic light with an ammeter (S314).
(E) A step of measuring at least one of reflected light reflected by the surface of the sample or transmitted light transmitted through the sample with a light meter (S312).
(F) A step of determining at least one of an ionization potential, a band gap, and a band lineup of the sample using the measured current value and the measured light amount of the reflected light or the transmitted light (S324, S326, S328).

Preferably, in step (b), a step (S306) of setting a sample at a predetermined position (for example, a sample stage) of the band lineup device is provided, but when the band lineup device is provided in the production line, It may be detected that the sample to be inspected has moved to a position where it can be inspected.
Preferably, in step (c), a part of the monochromatic light having a specific wavelength separated by the spectroscope is measured as a reference light using an optical system including a half mirror or a branch fiber, and a monochromatic light other than the reference light is obtained. It is good also as a step which irradiates light to a sample.

The band lineup measuring method of the present invention preferably further includes the following steps (g) to (i), wherein the band lineup is calculated from the ionization potential value and the band gap value.
(G) A step of separating only light of a desired wavelength into monochromatic light by operating the spectroscope from a wavelength from an infrared region to an ultraviolet region emitted from a light source unit by a control signal from a control device ( S310).
(H) It is determined whether or not the measurement wavelength range has been measured. If not, the step of operating the spectroscope to change the wavelength of the monochromatic light (S318 and S322).
(I) A step of turning off the DC voltage applied to the sample or the collector electrode when the process is completed (S320).

In the band lineup measuring method of the present invention, preferably, the method further includes the following steps (j) to (k), wherein the measurement position of the sample is changed.
(J) A step of recording the measured current value and the measured light amount value of reflected light or transmitted light in the storage device together with the position on the surface of the sample irradiated with monochromatic light (S316).
(K) A step of changing the position where the sample is irradiated with monochromatic light (S332).
(L) Preferably, a step (S330) of determining whether or not to change the measurement position and changing the measurement location by operating the stage unit when changing is also provided.
The band line-up apparatus of the present invention further includes a fluorescence spectrometer (a spectrometer with a CCD or a multichannel spectrometer with a CCD) provided on the side of measuring the reflected light of the sample with respect to the light irradiation unit 5. A band lineup measuring device having a measuring function is provided.

According to the present invention, the measurement accuracy of the band lineup can be improved. Specifically, by incorporating a function that allows simultaneous measurement of light and electrons in the band lineup measurement, errors due to differences in device characteristics are reduced compared to the case of separate devices, and sample loading, Since the shape, irradiation damage, and sample environment are the same, the measurement accuracy can be improved.
In addition, since it is a device having the simultaneous measurement function of light and electrons, and the location where the sample is held is the same, it is not necessary to change the sample handling, and human errors associated with the sample handling can be reduced. In addition, since the measurement time lag at the time of measurement with another measuring device can be reduced and measurement can be performed under the same conditions, more accurate measurement is possible.
Furthermore, by incorporating a calculation algorithm into the analysis software of the measurement analyzer, the band lineup values can be obtained directly based on the _EVBM and band gap values, and the measurement data analysis of the person in charge of the experiment can be performed easily.

FIG. 1 is a diagram showing the energy relationship of band lineup measurement. FIG. 2 is a block diagram of the main part of the band lineup measuring apparatus showing the first embodiment of the present invention. FIG. 3 is a flowchart for explaining a band lineup measurement procedure in the apparatus of FIG. FIG. 4 is a flowchart for explaining a band gap calculation procedure in the apparatus of FIG. FIG. 5 is a flowchart for explaining the ionization potential calculation procedure in the apparatus of FIG. 6A and 6B illustrate the results of band lineup measurement of the Si sample in the apparatus of FIG. 2, where FIG. 6A is a reflection measurement example of the Si sample, FIG. 6B is an ionization potential measurement example of the same Si sample, and FIG. An example of lineup values is shown. FIG. 7 is a main part configuration diagram of a band lineup measuring apparatus showing a second embodiment of the present invention, and shows a case including a half mirror optical system. FIG. 8 is a block diagram of a main part of a band lineup measuring apparatus showing a third embodiment of the present invention, and shows a case where a branch fiber optical system is included. FIG. 9 is a configuration diagram illustrating details of the branch fiber. FIG. 10 is a diagram showing the relationship between the electrode shape and the electrode arrangement, and shows the use of a half mirror optical system such as the apparatus of FIG. FIG. 11 is a diagram showing the relationship between the electrode shape and the electrode arrangement, and shows the use of a branch fiber optical system such as the apparatus of FIG. FIG. 12 is a flowchart showing a procedure for overall measurement in band lineup measurement. FIG. 13 is a flowchart showing a procedure in background / reference spectrum measurement. FIG. 14 is a flowchart showing the procedure of ionization potential calculation. FIG. 15 is a flowchart showing the procedure of band gap calculation. FIG. 16 is a flowchart showing the band lineup calculation procedure. FIG. 17 is a diagram showing the results of reflection measurement of an organic EL material, and shows each of Rubrene, Me-TPD, Alq3, and CuPc. FIG. 18 is a diagram showing the measurement result of the photoelectron yield of the organic EL material, and shows each of Rubrene, Me-TPD, Alq3, and CuPc. FIG. 19 is a diagram showing an example of the band lineup value of the organic EL material, and shows each of Rubrene, Me-TPD, Alq3, and CuPc. FIG. 20 is a diagram showing an example of fluorescence measurement of the fluorescent pen measured with the apparatus of FIG. FIG. 21 is a diagram showing an example of fluorescence measurement when the irradiation wavelength in Me-TPD measured by the apparatus of FIG. 8 is changed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments in which a band lineup measuring apparatus and a band lineup measuring method according to the present invention are suitably implemented will be described in detail with reference to the drawings.

<Band lineup device>
FIG. 2 is a block diagram of the main part of the band lineup measuring apparatus showing the first embodiment of the present invention. In FIG. 2, the band lineup measuring apparatus includes a light source unit 1, an electric system measuring unit 2, a sample setting unit 3, a spectroscope 4, an irradiation / reference / reflection optical system 5, a transmission optical system 7, and a logic control unit 8. Yes.

  The light source unit 1 includes a halogen lamp 12, a lens 13, a deuterium light source lamp 14, and a lens 15. The light source unit 1 emits continuous light, and can cover an infrared to ultraviolet wavelength band by combining, for example, a halogen lamp 12 and a deuterium light source lamp 14. As the light source unit 1, a xenon lamp can be used complementarily. The light source unit 1 can measure the band lineup using light of different wavelength bands generated from each lamp.

  The electrical measurement unit 2 includes a collector electrode 21, a negative voltage source Vee 22 connected to a sample holder 32, and an ammeter 23. The ammeter 23 measures the current flowing through the sample 31 and the collector electrode 21. The collector electrode 21 is provided between the tip of the irradiation / reflection optical fiber 59 and the sample 31.

  The sample setting unit 3 includes a sample 31, a sample holder 32, a stage unit 33, an air / vacuum vessel 34, and an electrical connection window 36. The sample holder 32 holds the sample 31 and puts it in a state suitable for band lineup measurement. The stage unit 33 is a sample stage on which the sample holder 32 is placed, and is also equipped with a mechanism for moving the sample holder 32 in the horizontal direction on the left and right and in the vertical direction. The atmosphere / vacuum container 34 accommodates the sample 31, the sample holder 32, and the stage unit 33, and also accommodates the distal end portion of the irradiation and reflection optical fiber 59, the transmission optical fiber, or the distal end portion of the lens 71. By connecting a vacuum pump or a gas inlet to the atmosphere / vacuum container, the pressure, humidity, atmosphere gas, etc. in the atmosphere / vacuum container can be controlled. The electrical connection window 36 is a window that accommodates electrical wiring that connects the sample holder 32 and the ammeter 23, and maintains the pressure and measurement environment of the atmosphere / vacuum vessel 34.

  The spectroscope 4 includes mirrors 41, 42, 44 and a diffraction grating 43 inside. The spectroscope 4 is different with respect to the incident angle through the paths of the mirrors 41 and 42, the diffraction grating 43, and the mirror 44 in the spectroscope with respect to the light from the infrared region to the ultraviolet region input from the light source unit 1. By changing the angle in the direction, light having a specific wavelength (monochromatic light) can be output from the spectroscope 4.

  The irradiation / reference / reflection optical system 5 as the light irradiation unit 5 includes a lens 51, a half mirror 52, lenses 53, 54 and 55, a housing unit 56, and an irradiation and reflection optical fiber 59. Independent of the light irradiation unit 5, a reference light quantity meter 57 and a reflected light quantity meter 58 are provided. As the irradiation optical system, among the irradiation / reference / reflection optical system 5, the lens 51, the half mirror 52, the lens 53, the housing unit 56, and the irradiation optical fiber 59 correspond. As the reference optical system, a lens 55 and a reference light quantity meter 57 correspond to each other. As a reflection optical system, a lens 54, a reflected light quantity meter 58, and a reflection optical fiber 59 are supported. The reference light quantity meter 57 and the reflected light quantity meter 58 may be a multichannel spectroscope (CMM) with a CCD, or a photodiode (PD) or a thermopile, for example. The lenses 51, 53, 54, and 55 are used for condensing light, and are shown here as convex lenses. However, they may be achromatic lenses from which chromatic aberration has been removed, as long as they can condense.

The transmission optical system 7 includes a transmission optical fiber 71 and a transmission light quantity meter 72. A lens may be used instead of the transmission optical fiber 71. The transmitted light quantity meter 72 may be a multi-channel spectrometer (CMM) with a CCD, or a photodiode (PD) or a thermopile, for example.
The logic control unit 8 includes a storage device 81 for storing various measurement data of the ammeter 23, the reference light light meter 57, the reflected light light meter 58, and the transmitted light light meter 72, and various measurement data from the storage device 81. And a control device 83 that outputs an operation signal to the spectroscope 4 and the stage unit 33 based on the data of the storage device 81 and the analysis device 82.

The principle of measurement in the apparatus configured as described above will be described next.
For the continuous light emitted from the light source unit 1, light having a specific wavelength is selected by the spectroscope 4 and sent to the irradiation / reference / reflection optical system 5. In the irradiation / reference / reflection optical system 5, a part (several percent) of the monochromatic light passed by the half mirror 52 is reflected in the direction of the reference light quantity meter 57, and the remaining many monochromatic lights are used for irradiation and reflection. Guide to optical fiber 59. Then, the monochromatic light scattered and reflected by the sample 31 is guided to the reflected light quantity meter 58. Further, when the sample is a light transmissive material, the transmitted light is guided to the transmitted light quantity meter 72 of the transmission optical system 7. In the embodiment of FIG. 2, the reflection optical fiber 59 and the transmission optical fiber 71 are used. However, a lens may be used without using the optical fiber. Further, when the sample is a material that does not transmit light, the transmission optical system 7 and the transmitted light quantity meter 72 may be omitted in the band lineup device.

  In order to efficiently measure electrons, a negative voltage source Vee is connected to the sample holder 32, and tens to hundreds of volts are applied to the sample as a negative voltage. At this time, the collector electrode 21 placed immediately above the sample is set to the ground potential. Moreover, you may use as the collector electrode 21 by making the irradiation and reflection optical fiber 59 used for irradiation into a ground potential. As the ammeter 23, a source meter capable of applying a voltage can be used.

  Irradiation light is irradiated from a vertical position (Z direction) with respect to the sample. The stage unit 33 is an XYZ stage having a plane on which the sample is placed. The sample holder 32 is placed on the XYZ stage, the sample 31 is placed, and the sample placed by the stepping motor or manual control is held on the optical axis. On the other hand, it can be moved in the X, Y and Z axis directions. Thereby, the sample holder 32 and the sample 31 placed on the stage unit 33 can be moved to predetermined positions. The sample holder 32 and the stage unit 33 are provided with a hole and a space for a transmission optical system so that transmission measurement can be performed.

<Measurement method>
Next, a band lineup measuring method will be described with reference to the drawings and flowcharts. FIG. 3 is a flowchart showing an example of a band lineup measurement procedure.
First, of the light from the infrared region to the ultraviolet region emitted from the light source unit 1, the spectroscope 4 is operated by the control signal from the control device 83 to output only light having a desired wavelength as monochromatic light (S01). The irradiation / reference / reflection optical system 5 is used to measure a part of monochromatic light output from the spectroscope 4 as reference light, and the remainder is irradiated to the sample 31 through the irradiation / reflection light optical fiber 59 (S02). .

Next, when the sample 31 is irradiated with light, the current value flowing from the ground to the sample is measured by the ammeter 23, and the reflected light reflected from the sample surface is simultaneously measured by the reflected light quantity meter 58. When the material is transmissive, the transmitted light is measured by the transmitted light quantity meter 72 (S03). The measured current value, reference light amount, reflected light amount, and transmitted light amount are recorded in the storage device 81 (S04).
Here, the control device 83 determines whether or not the measurement within the initially set measurement wavelength range is completed (S05), and when the measurement with all the measurement wavelengths is not completed (NO in S05), the spectroscope 4 is operated to change the wavelength (S06). Moreover, after the process of S06 is complete | finished, it returns to S02 and performs the process after S02.

  When measurement using all measurement wavelengths is completed (YES in S05), the measurement result recorded in the storage device 81 is sent to the analysis device 82, the ionization potential is determined (S07), and then the band gap is determined (S08). ). Thereafter, the band lineup is determined from the value of the ionization potential and the value of the band gap (S09).

Then, the control device 83 determines whether or not to change the measurement position (S10). When changing the measurement position (YES in S10), the stage unit 33 is operated to change the measurement location (S11). ). Moreover, after the process of S11 is complete | finished, it returns to S01 and performs the process after S01.
If the measurement position is not changed in S10 (NO in S10), the measurement is terminated.
In this way, by using the same light source and optical system, and having the functional equipment that can simultaneously measure the current value and the light amount of the same location in the same sample, by analyzing the recorded multiple measurement results, The measurement accuracy of the band lineup can be improved.

<Example of band lineup measurement>
FIG. 4 is a detailed diagram of the algorithm for determining the band gap in S08 of FIG. 3, and is a flowchart for explaining the band lineup calculation procedure in the apparatus of FIG. The band gap determination algorithm in FIG. 4 is an algorithm for determining the band gap from the obtained reflected light amount, reference light amount, or transmitted light amount. A photodiode is used to measure the amount of light. Since the sensitivity coefficient of the photodiode varies depending on the wavelength, it is necessary to calibrate with the sensitivity coefficient. Some measurement materials cannot be measured for transmission.

The reference light quantity (rPD) is converted into a calibrated light quantity using the wavelength sensitivity characteristic (rSENS) of the measuring instrument (S102).
C-rPD = rPD / rSENS (1)
The reflected light amount (fPD) is converted into a calibrated light amount by using the wavelength sensitivity characteristic (fSENS) of the measuring instrument (S104).
C-fPD = fPD / fSENS (2)
At that time, the subsequent processing in the analysis device 82 changes depending on whether or not there is transmitted light (S106). If there is transmitted light, the transmitted light amount (tPD) is also calibrated by the wavelength sensitivity coefficient (tSENS) (S108).
C-tPD = tPD / tSENS (3)
Next, the analysis device 82 divides the calibration transmitted light amount by the calibration reference light amount to obtain a transmittance (Trans) (S110).
Trans = C-tPD / C-rPD (4)
Then, a graph of transmittance with respect to incident photon energy is created (S112), and a band gap is obtained from the transmittance of the graph (S114).

On the other hand, if there is no transmitted light, the ratio of the calibration reflected light amount and the calibration reference light amount is measured to obtain the relative reflectance (Refl) (S116).
Refl = C−fPD / C−rPD (5)
Next, the analysis device 82 converts the relative reflectance into the relative absorption rate (abs) using the Kubelka-Munk conversion (S118) (Non-Patent Documents 4 and 6).
abs = (1−Refl) ² / ( ² × Refl) (6)
Then, the analyzer 82 creates a graph with respect to the incident energy (E) on the horizontal axis and the incident photon energy on the vertical axis (S120), and a band gap is obtained from the absorptance of the graph (S122).

FIG. 5 is a detailed diagram of an algorithm for determining the ionization potential in S07 of FIG. 3, and is a flowchart for explaining the ionization potential calculation procedure in the apparatus of FIG. The ionization potential determination algorithm in FIG. 5 is an algorithm for determining the ionization potential from the reference light amount and the current value. As described above, the reference light amount measurement is performed by the photodiode, and the wavelength sensitivity correction is necessary. First, wavelength sensitivity calibration is performed (S202).
C-rPD = rPD / rSENS (7)
Then, in order to convert to the number of photons, the calibration light amount C-rPD is divided by the photon energy (E) at each wavelength to obtain the relative photon number (NP) (S204).
NP = (C−rPD) / E (8)
In order to obtain the yield per photon (PYS), the current value (CI) is divided by the number of relative photons (S206).
PYS = CI / NP (9)
In order to obtain the threshold value with the Fowler function, the square root of the value obtained in S206 is taken (S208). A graph is created (S210), and the ionization potential is determined (S212).

The band lineup is obtained from these two values. _EVBM is consistent with the ionization potential. The _EVBM is obtained by adding the band gap value to this value.

  Here, a measurement example of the band lineup will be described with reference to the drawings. FIG. 6A is a diagram showing an example of the band gap obtained from the result of the reflection measurement of the Si sample using the algorithm of FIG. FIG. 6B is a diagram showing an example of the ionization potential obtained using the algorithm of FIG. 5 from the result of current measurement of the same Si sample. FIG. 6C is an example of band lineup values obtained from the measured values obtained in (a) and (b).

The Si sample is a wafer-like single crystal. In this sample, since the transmission measurement cannot be performed, the band gap is obtained from the reflection measurement. As described above, the band gap is obtained as 1.10 eV from FIG. As shown in FIG. 6B, the ionization potential is 5.22 eV. Therefore, as shown in FIG. 6C, E _VBM = 5.22 eV and E _CBM = 4.12 eV can be obtained.

FIG. 7 is a main part configuration diagram of a band lineup measuring apparatus showing a second embodiment of the present invention, and shows a case including a half mirror optical system. In FIG. 7, the same reference numerals are given to the same operations as those in FIG. 2 described above, and the description thereof is omitted.
The embodiment of FIG. 7 is an improved version of the embodiment of FIG. The electrical measurement unit 2 is further provided with a positive voltage source Vcc 24 and an ammeter 25. The irradiation / reference / reflection optical system 5 is further provided with a secondary light / stray light filter 60 and a condenser lens unit 61.

The positive voltage source Vcc24 has one end grounded and the other end connected to the collector electrode 21 via the electrical connection window 36. The positive voltage source Vcc24 applies a voltage of several volts to several hundred volts to the collector electrode 21 in order to efficiently measure electrons.
The secondary light / stray light filter 60 removes secondary light and stray light, which are noises, so that a more accurate measurement value can be obtained from the light of the signal component. The monochromatic light output from the spectroscope 4 Is transmitted to the half mirror 52. The condensing lens unit 61 is provided at the tip of the irradiation and reflection optical fiber 59 so as to condense the irradiation light on the surface of the sample 31 so that the reflected light from the sample surface easily enters the reflection optical fiber 59. To do.
According to the second embodiment, it is possible to remove the influence of the measurement environment and apparatus characteristics such as sample setting in the case of measuring with separate measurement apparatuses, and to realize a highly accurate band lineup measurement.

FIG. 8 is a block diagram of a main part of a band lineup measuring apparatus showing a third embodiment of the present invention, and shows a case where a branch fiber optical system is included. In FIG. 8, the same reference numerals are attached to the same components as those in FIG.
In the embodiment of FIG. 8, the optical components of the irradiation / reference / reflection optical system in the embodiments of FIGS. 2 and 7 are replaced with branching fibers. The branch fiber 9 includes a spectroscope-side fiber 91, a reference optical fiber 92, a reflective optical fiber 93, an irradiation optical fiber 94, and a fiber branching unit 95.

9A and 9B are configuration diagrams for explaining the details of the branch fiber. FIG. 9A is an overall view of the apparatus, FIG. 9B is an end view on the irradiation light side, FIG. 9C is an end view on the reference light side, and FIG. (E) is an end view on the spectroscope side. The spectroscope-side fiber 91 is arranged vertically in the fiber so as to match the distribution of the monochromatic light emitted from the spectroscope 4 because the monochromatic light is emitted linearly at the exit of the spectroscope 4. The reference optical fiber 92 branches out monochromatic light incident on the spectroscope-side fiber 91 by a fiber branching unit 95 for reference light. One end of the reflective optical fiber 93 guides the reflected light to the reflected light photometer 58, and the other end is bundled with the irradiation optical fiber 94 and faces the sample. The irradiation optical fiber 94 irradiates the sample with the irradiated monochromatic light other than that for irradiation reference light being rearranged by the fiber branching section 95 for sample irradiation.
In the branched fiber configured as described above, the light reflected on the sample passes through the reflective optical fiber 93 bundled with the irradiation optical fiber 94, is branched by the fiber branching unit 95, passes through the reflective optical fiber 93, and is reflected light. Guided to a photometer 58.

  FIG. 10 is a diagram showing the relationship between the electrode shape and the electrode arrangement, and shows the use of a half mirror optical system such as the apparatus of FIG. 10, (a1) is a side view of the ring electrode, (a2) is a plan view of the ring electrode, (b1) is a side view of the short needle electrode, (b2) is a plan view of the short needle electrode, (c1) ) Is a side view of the mesh electrode, and (c2) is a plan view of the mesh electrode.

  In FIG. 10, the irradiation and reflection optical fiber 59, the condensing lens 61, the collector electrode 21, and the sample 31 are positioned in the vertical direction in this order. The collector electrode 21 is disposed immediately above the sample 31 and measures electrons. The distance between the collector electrode 21 and the sample 31 is, for example, 1.0 mm or less in measurement under atmospheric pressure. Although it is preferable that both measurement accuracy and measurement work efficiency can be achieved, the measurement accuracy may be increased to 0.5 mm or less in consideration of the mean free path of electrons. As the electrode shape, for example, on the optical path of the irradiation beam, a ring-shaped electrode 21a that does not interfere with the irradiation beam diameter, a short needle-shaped electrode 21b that covers a part of the irradiation beam diameter, or a mesh shape that is approximately the same as the irradiation beam diameter. The electrode 21c is used.

  FIG. 11 is a diagram showing the relationship between the electrode shape and the electrode arrangement, and shows the use of a branch fiber optical system such as the apparatus of FIG. 11, (a1) is a side view of the ring-shaped electrode, (a2) is a plan view of the ring-shaped electrode, (b1) is a side view of the short needle-shaped electrode, (b2) is a plan view of the short needle-shaped electrode, (c1 ) Is a side view of the mesh electrode, and (c2) is a plan view of the mesh electrode.

<Measurement method>
Next, a band lineup measuring method will be described with reference to the drawings and flowcharts. FIG. 12 is a flowchart showing a procedure for overall measurement in band lineup measurement.
First, the control device 83 determines whether a background (Dark) spectrum and a reference (Ref) spectrum necessary for transmission and reflection measurement have already been acquired (S302). If not acquired, it is acquired according to the background / reference spectrum measurement flowchart described later (S304). If acquired, the measurement sample 31 is set in the sample holder 32 (S306). A voltage is applied to the sample 31 and / or the electrode 21 (S308). Of the light from the infrared region to the ultraviolet region emitted from the light source unit 1, the spectroscope 4 is operated by the control signal from the control device 83 to output only light having a desired wavelength as monochromatic light (S310). The monochromatic light output from the spectroscope 4 is separated by using the optical system 5 including the half mirror 52 or the branch fiber 9, partly as reference light, the rest as irradiation light, and the light reflected by the sample. The reference light quantity meter 57, the reflected light quantity meter 58, and the transmitted light quantity meter 72 measure the reference light quantity, the reflected light quantity, and the transmitted light quantity when the sample is a light-transmitting material (S312). .

Next, the current value flowing between the sample 31 and the collector electrode 21 when the sample 31 is irradiated with light is measured by the ammeter 23 or 24 (S314). The measured current value and light amount are recorded in the storage device 81 (S316).
Here, it is determined whether or not the measurement within the initially set measurement wavelength range has been completed (S318), and when measurement with all measurement wavelengths has not been completed (NO in S318), the control device 83 determines that the spectroscope 4 To change the wavelength of the monochromatic light (S322). In addition, after the process of S322 is completed, the process returns to S312 and the processes after S312 are performed.

  When measurement using all measurement wavelengths is completed (YES in S318), the DC voltage applied to the sample 31 and / or the collector electrode 21 is turned off (S320). The measurement result recorded in the storage device 81 is sent to the analysis device 82. The analysis device 82 determines each value according to an ionization potential determination flowchart (S324), which will be described later, and then a band gap determination flowchart (S326). Thereafter, from the ionization potential value and the band gap value, the analysis device 82 determines the band lineup according to the band lineup determination flowchart (S328).

Then, the control device 83 determines whether or not to change the measurement position (S330). When the measurement position is changed (YES in S330), the measurement unit is changed by operating the stage unit 33 (S332). . Further, after the processing of S332 is completed, the control device 83 returns to S310 and performs the processing after S310.
On the other hand, if the measurement position is not changed in S330 (NO in S330), the measurement is terminated.

Next, a background / reference spectrum measurement flowchart will be described with reference to FIG.
In order to determine the relative transmittance and the relative reflectance, both the background spectrum and the reference spectrum must be measured. First, the control device 83 determines whether to measure a background (Dark) spectrum or a reference (Ref) spectrum (S402). In the case of the background spectrum, nothing is set in the sample holder 32 (S404). In the case of the reference spectrum, the reference substance is set in the sample holder 32 (S406). Subsequent operations are the same. Among the light from the infrared region to the ultraviolet region emitted from the light source unit 1, the spectroscope 1 is operated by the control signal from the control device 83 to output only light of a desired wavelength as monochromatic light. (S408). The reference light quantity meter 57, the reflected light quantity meter 58, and the transmitted light quantity meter 72 measure the light quantity of the reference light, the reflected light, and the transmitted light when the sample is a light-transmitting material (S410). . The measured light quantity is recorded in the storage device 81 (S412).

Next, the control device 83 determines whether or not the measurement within the initially set measurement wavelength range is completed (S414), and when the measurement with all the measurement wavelengths is not completed (NO in S414), the spectroscope 4 is operated to change the wavelength (S416). Further, after the process of S416 is completed, the process returns to S410 and the subsequent processes are performed.

<Example of band lineup measurement>
The storage device 81 records the light amount and current value measured while scanning the wavelength according to the flowchart of FIG. From the obtained spectrum, the analysis device 82 determines the band lineup according to the ionization potential determination flowchart, the band gap determination flowchart, and the band lineup determination flowchart.

The ionization potential determination flowchart of S324 in FIG. 12 determines the ionization potential from the reference light amount and the current value as shown in FIG. As described above, the reference light amount measurement is performed by a photodiode, and wavelength sensitivity correction is necessary. There are two types of sensitivity correction: one that performs sensitivity correction on the spot for each measurement wavelength, and one that performs post-measurement correction based on a certain wavelength. Here, the sensitivity-corrected light amount (C-rPD) is used. The analysis device 82 calculates the relative photon number (NP) by dividing C-rPD by the energy of the photon at each wavelength in order to convert the light quantity subjected to wavelength sensitivity calibration into the number of photons (S502).
NP = (C-rPD) / E (10)

In order to obtain a yield per photon (photoelectron yield: PYS), the analysis device 82 divides the current value (CI) by the relative number of photons (NP) (S504).
PYS = CI / NP (11)
In order to obtain the threshold value assuming the Fowler function, the square root of the value obtained in S504 is taken (S506).
S-PYS = (PYS) ^1/2 (12)
The analysis device 82 creates a graph with the horizontal axis representing irradiation energy and the vertical axis representing S-PYS (S508). Then, a tangent line is drawn at the position of the inflection point in the graph, and the energy at the intersection with the background line is determined as the ionization potential (S510).

The band gap determination flowchart of S326 in FIG. 12 determines the band gap from reflection measurement or transmission measurement as shown in FIG.
The analysis device 82 determines whether there is a transmission measurement depending on whether the measurement device is equipped with a transmission measurement facility or is a permeable sample (S602). If there is a transmission measurement, the relative transmittance (RT) is obtained from the transmission measurement data (TM) using the background data (Tdark) and the reference data (Tref) (S604).
RT = (TM-Tdark) / (Tref-Tdark) (13)
Next, a graph of vertical axis RT and horizontal axis E is created (S620). The absorption edge is obtained from the graph (S622).

When there is no transmission measurement (NO in S602), the relative reflectance (RR) is obtained from the reflection measurement data (RM) using the background data (Rdark) and the reference data (Rref) (S606).
RR = (RM-Rdark) / (Rref-Rdark) (14)
After obtaining the relative reflectance RR, the absorption coefficient (a) is obtained using two calculation methods. Refractive index (n) and extinction coefficient (k) are obtained using Kramers-Kronig transformation (Non-Patent Document 5) using RR (S608). Then, the absorption coefficient (a) is obtained using the extinction coefficient (S612).
a = 4πk / λ (15)
Here, λ is a wavelength.
On the other hand, the absorption coefficient (a) is obtained using the Kubelka-Munk transform (Non-patent Document 6) (S610).
a / s = (1-RR) (1-RR) / (2RR) (16)
Here, s = 1.

Since the absorption coefficient is obtained by each conversion method, the subsequent processing is the same. When direct transition is assumed, a graph of vertical axis: (aE) ² and horizontal axis: E is created from the relationship of the following equation (S614).
a = A · (E−Eg) ^1/2 / E (17)
If indirect transition is assumed, a graph of vertical axis: (aE) ^1/2 and horizontal axis: E is created from the relationship of the following equation (S616).
a = B · (E−Eg) ² / E (18)
A tangent line is drawn at the position of the inflection point at the lowest energy in the graph, and the energy at the intersection with the background line is defined as a band gap (S618). The band gap can be obtained from each of them, but the value to be used is determined in consideration of the material characteristics of the measurement object, and the band gap is determined (S624).

The band lineup determination flowchart of S326 in FIG. 12 determines the band lineup from the band gap value and the ionization potential value as shown in FIG. First, the values of the band gap (Eg) and the ionization potential (IP) are read (S702). Next, the level of the lower end of the conductor (LUMO): electron affinity (χ) is obtained (S704).
χ = IP−Eg (19)
Then, a chart displaying the vacuum level, χ, IP, and Eg is created (S706).

  FIG. 17 is a diagram illustrating an example of a band gap obtained by reflection measurement of Rubrene, Me-TPD, Alq3, and CuPC used for the organic EL material. Rubrene (5,6,11,12-tetraphenyl naphthacene) is an aromatic hydrocarbon of a tetracene derivative. A rubrene single crystal has the highest mobility among organic semiconductors and is used for organic EL (OLED), organic field effect transistor (OFET) and the like. Me-TPD (N, N, N ′, N′-Tetrakis (4-methylphenyl) benzidine) is an aromatic amine. Since it has high hole mobility, it is used as a hole transport material in organic EL materials. Alq3 is tris (8-hydroxyquinolinato) aluminum, a complex based on bidentate coordination of aluminum metal and three 8-quinolinol ligands. It is. CuPC is copper phthalocyanine (Phthalocyanine, Copper complex), and is a copper complex of a cyclic compound having a structure in which four phthalimides are bridged by nitrogen atoms.

FIG. 18 is a diagram showing an example of ionization potential measurement of the same sample, which is shown here as a photoelectron yield measurement result. FIG. 19 is an example of band lineup values obtained from the measurement values obtained in FIGS. 17 and 18.
The sample used for measurement is a powdery substance, and transmission measurement cannot be performed, so the band gap is obtained from reflection measurement. As described above, the band gap can be obtained as 2.2 eV, 3.1 eV, 2.9 eV, and 1.6 eV for each of Rubrene, Me-TPD, Alq3, and CuPC from FIG. From FIG. 18, the respective ionization potentials are obtained as 5.35 eV, 5.5 eV, 5.9 eV, and 5.25 eV. Therefore,其's valence band maximum _{E VBM} as in Figure 19 is equal to the ionization potential,其' s conduction band _{E CBM} is possible to obtain 3.15 eV, 2.4 eV, 3.0 eV, and 3.65eV Can do.

<Fluorescence measurement function>
The band lineup apparatus having the fluorescence function measurement is based on the apparatus shown in FIG. 7 or FIG. 8, and a fluorescence spectrometer is installed in the reflection measurement unit 58. As the fluorescence spectrometer, a CCD-equipped spectrometer or a CCD-equipped multichannel spectrometer can be used. In the fluorescence measurement, a wavelength different from the incident wavelength separated by the spectroscope 4 is measured. When the sample is a fluorescent material, when irradiated with ultraviolet light, reflected light or light emission having a wavelength different from the wavelength of the irradiated ultraviolet light is observed. Measure with a multichannel spectrometer with CCD.

  FIG. 20 is a diagram showing an example of fluorescence measurement measured by the apparatus shown in FIG. 8. (A) is a spectroscopic diagram, the vertical axis is emission intensity (Photoluminecence: PL [au]], and the horizontal axis is wavelength. Yes, (B) shows the green, yellow, orange and pink of the highlighter. Here, a case where the incident wavelength obtained by the spectroscopy of the spectroscope 4 is 395 nm is shown. For the green color of the fluorescent pen, fluorescence wavelengths having peaks at the incident wavelengths of 395 nm and 510 nm are observed. For the yellow color of the fluorescent pen, fluorescence wavelengths having peaks at the incident wavelengths of 395 nm and 510 nm are observed. For the orange color of the fluorescent pen, fluorescence wavelengths having peaks at incident wavelengths near 395 nm and 590 nm are observed. With respect to pink of the fluorescent pen, fluorescence wavelengths having peaks at the incident wavelengths of 395 nm and around 600 nm are observed.

  FIG. 21 is a diagram showing an example of fluorescence measurement in which the multichannel spectrometer with CCD is installed in the reflection measuring unit 58 in the apparatus of FIG. The measurement sample is Me-TPD. The vertical axis indicates the emission intensity and the horizontal axis indicates the wavelength. Even if the irradiation wavelength is changed, the emission wavelength does not change, but the intensity changes depending on the wavelength. The wavelength at maximum emission is around 420 nm.

In the above embodiment, the continuous light emitted from the light source unit has been shown to cover all regions of the wavelength in the infrared region, the wavelength in the visible light region, and the wavelength in the ultraviolet region. It is not limited. For example, the light source unit includes only a part of the wavelength in the infrared region, the wavelength in the visible light region, and the wavelength in the ultraviolet region, as in the case of measuring with respect to specific matters of the band lineup based on the known properties of the material to be measured. It may emit continuous light.
Moreover, in said embodiment, although the case where both the transmitted light measurement part and the reflected light measurement part are provided is shown, this invention is not limited to this. For example, when the measurement target sample has light transmittance, only the transmitted light measurement unit may be used. Further, when the measurement target sample is not light transmissive, only the reflected light measurement unit may be used.

Furthermore, in the above-described embodiment, Kramers-Kronig transformation and Kubelka-Munk transformation are shown as analytical expressions in the analysis device, but the present invention is not limited to this, and equivalents that achieve the same purpose The following conversion formula can be used. Further, the above-described embodiment is merely illustrative of the present invention, and includes modifications by devices, devices, and materials that are obvious to those skilled in the art.
Furthermore, in the above embodiment, the case where the characteristic value of the sample is measured by batch processing as a band lineup measuring device has been shown, but the present invention is not limited to this, and is manufactured by being installed in a production line. The sample may be configured to continuously measure the sample.

  As described above, according to the band lineup measuring apparatus of the present invention, the band lineup can be accurately measured without changing the sample state by irradiation even with an organic material that is easily damaged by high-energy ultraviolet light. Therefore, band line-up measurement can be performed with high accuracy in the fields of semiconductors, materials such as nanomaterial creation, protein science and genetic engineering, and the present invention can greatly contribute to the development of industry.

DESCRIPTION OF SYMBOLS 1 Light source part 2 Electrical system measurement part 21 Collector electrode 22, 24 Voltage source 23, 25 Ammeter 3 Sample installation part 31 Sample 32 Sample holder 33 Stage unit, moving mechanism, sample stand 4 Spectrometer 5 Light irradiation part, irradiation optical system , Irradiation / reference / reflection optical system 52 half mirror 57 light meter for reference light, reference light measuring unit 58 light meter for reflected light or multichannel spectrometer with CCD, reflected light measuring unit 59 optical fiber 60 for irradiation and reflection secondary light Stray light filter 61 Condensing lens 7 Transmission optical system 71 Optical fiber or lens for transmission 72 Light meter for transmitted light or multi-channel spectrometer with CCD, transmitted light measurement unit 8 logic control unit 81 storage device 82 analysis device 83 control device 9 light Irradiation unit, optical branching fiber for irradiation and reflection

Claims (15)

A light source that emits continuous light including at least one of an infrared wavelength, a visible wavelength, and an ultraviolet wavelength;
A spectrometer that extracts light of a specific wavelength from the continuous light;
A light irradiation unit that irradiates the sample with light of the specific wavelength as irradiation light ;
A light quantity measurement unit comprising at least one of a reflected light measurement unit that measures light reflected from the surface of the sample caused by the irradiation light, and a transmitted light measurement unit that measures light transmitted through the sample;
A collector electrode provided between the light irradiation unit and the sample;
A current measuring unit that measures the current flowing between the sample and the collector electrode caused by the irradiation light simultaneously with the measurement of light by the light amount measuring unit ;
A control device for controlling a specific wavelength extracted by the spectrometer;
And a band lineup apparatus capable of calculating a valence band upper end energy (E _VBM ) and a conduction band lower end energy (E _CBM ) of the sample from the measurement results of the light quantity measurement unit and the current measurement unit. Furthermore, it has a moving mechanism that moves including at least one of the vertical direction and the parallel direction with respect to the optical axis of the light irradiating the sample,
The band lineup apparatus according to claim 1, wherein the control device controls the position of the surface of the sample irradiated by the light irradiation unit by controlling the moving mechanism. Furthermore, a sample holder for installing the sample,
The collector electrode provided between the sample and the light irradiation unit;
The band lineup apparatus according to claim 1, further comprising a DC voltage source that applies a DC voltage to at least one of the sample holder and the collector electrode.   The band lineup apparatus according to claim 3, wherein the collector electrode is made of metal, and a distance between the collector electrode and the sample is 1.0 mm or less in measurement under atmospheric pressure.   The collector electrode shape is a ring shape that does not interfere with the beam diameter of the irradiation light on the optical path of the irradiation light, a short needle shape that covers a part of the beam diameter of the irradiation light, or a mesh that is approximately the same as the beam diameter of the irradiation light The band lineup apparatus according to claim 3 or 4, wherein the band lineup apparatus is at least one of a shape.   6. The band lineup apparatus according to claim 1, wherein the light source unit includes both a halogen light source and a deuterium light source.   The light irradiation unit includes an optical system including a half mirror that separates the irradiation light and the reflected light from light of a specific wavelength extracted by the spectroscope, or an optical including a fiber that branches each of the irradiation light and the reflected light. The band lineup apparatus according to claim 1, further comprising a system. The light irradiation unit further includes the optical system including a half mirror, or the optical system including a fiber, which separates reference light from light of a specific wavelength extracted by the spectrometer.
8. The band lineup apparatus according to claim 7, wherein the light quantity measurement unit includes a reference unit that extracts a part of light irradiation and measures it as reference light.   9. The light irradiation unit according to claim 1, wherein the light irradiation unit has an optical fiber for irradiation light and has a function corresponding to the collector electrode by setting the optical fiber for irradiation light to a ground potential. The band lineup device according to item 1. Using the valence band top energy (E _VBM ) and conduction band bottom energy (E _CBM ) of the sample, the following equations (i) and (I) for the ionization potential value (IP) and the band gap value (Eg): The band lineup apparatus according to claim 1, wherein a band lineup (E _VAC , E _VBM , E _CBM ) is calculated from ii).
IP = E _VAC -E _VBM (i)
Eg = E _CBM -E _VBM (ii) A band lineup measuring method using the band lineup apparatus according to claim 1,
Acquiring a background (dark) spectrum and a reference (ref) spectrum required for at least one of reflection measurement and transmission measurement;
Applying a DC voltage to at least one of the sample or the collector electrode;
Irradiating the sample with monochromatic light of a specific wavelength separated by a spectrometer;
Measuring a current value flowing between the collector electrode and the sample when the sample is irradiated with the monochromatic light with an ammeter;
Measuring at least one of the reflected light reflected by the surface of the sample or the transmitted light transmitted through the sample with a light meter simultaneously with the measurement of the current value by the ammeter ;
Determining at least one of a value of an ionization potential of the sample, a value of a band gap , and a band lineup using the measured current value and the measured light amount of the reflected light or the transmitted light;
A band lineup measuring method characterized by comprising: A band lineup measuring method using the band lineup apparatus according to claim 11,
The step of irradiating the sample includes measuring a part of the monochromatic light having a specific wavelength separated by the spectroscope as a reference light using an optical system or a branching fiber including a half mirror, and producing a monochromatic light other than the reference light. A band lineup measuring method, which is a step of irradiating the sample with light. A band lineup measuring method by the band lineup apparatus according to claim 11 or 12, further comprising:
Of the wavelengths from the infrared region to the ultraviolet region emitted from the light source unit, operating the spectroscope by a control signal from a control device, and separating only light of a desired wavelength into monochromatic light,
It is determined whether or not the measurement wavelength range measurement is completed, and if not completed, the wavelength of the monochromatic light is changed by operating the spectrometer, and if completed, at least the sample or the collector electrode Turning off one DC voltage application;
The a, band lineup measuring method characterized by the operations of the band lineup from the value of the band gap and the value of the ionization potential. A band lineup measuring method using the band lineup apparatus according to any one of claims 11 to 13, further comprising:
Recording the measured current value and the measured light amount value of the reflected light or transmitted light in a storage device together with the position on the surface of the sample irradiated with the monochromatic light;
Changing the position of irradiating the sample with the monochromatic light;
Band lineup measuring method, wherein a has, and so to change the measurement position of the sample. The band lineup device according to any one of claims 1 to 10,
A band lineup measuring apparatus having a fluorescence measurement function, further comprising a fluorescence spectrometer provided on the light irradiation unit on a side where the reflected light of the sample is measured.