CN103529310B - A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED - Google Patents
A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED Download PDFInfo
- Publication number
- CN103529310B CN103529310B CN201310459347.8A CN201310459347A CN103529310B CN 103529310 B CN103529310 B CN 103529310B CN 201310459347 A CN201310459347 A CN 201310459347A CN 103529310 B CN103529310 B CN 103529310B
- Authority
- CN
- China
- Prior art keywords
- test sample
- electric field
- reverse biased
- polarized electric
- gan base
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
- Testing Of Individual Semiconductor Devices (AREA)
- Led Devices (AREA)
Abstract
The invention discloses a kind of method utilizing photoluminescence spectrometry GaN base LED polarized electric field, the method comprises making GaN base LED and tests sample, utilize and test sample described in the complete irradiation of laser and measure its photocurrent exported and photovoltage, positive voltage is connect to the n-electrode of described test sample, p-electrode connects negative voltage, form reverse biased, the reverse biased equaling photovoltage is applied to described test sample, measure its photoluminescence spectrum, and record its emission wavelength, then substep increases reverse biased, and measure its spectrum and wavelength, when wavelength transfers to elongated by shortening gradually, stop increasing reverse biased and stop measuring, utilize and stop reverse biased when measuring to deduct the polarizing voltage that photovoltage obtains described test sample, the polarized electric field of test sample is calculated according to this polarizing voltage.The present invention is simple to sample requirement, and sample preparation is convenient, can obtain test result quickly, is conducive to meeting the active demand of producing and to test data in research and development technique.
Description
Technical field
The present invention relates to semiconductor LED technical field of measurement and test, be specifically related to a kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED, the present invention is applicable to the measurement of the polarized electric field of all GaN base LED such as blue light, green glow, purple light and ultraviolet light.
Background technology
Along with the fast development of GaN base white light LEDs, LED efficiency has had large increase, progressively replaces illumination incandescent lamp used and fluorescent light at present at present.But its efficiency relative theory value also has very large room for promotion, and particularly under big current, the efficiencydroop phenomenon of LED is very serious.About droop effect, very large factor is the GaN polar growth that polar substrate material brings, thus define large built-in polarized electric field (piezoelectric polarization electric field) in LED inside, and under Bulk current injection, further increase band curvature again, thus enhance the polarization effect of LED.For this reason, a lot of method of the growing nonpolar GaN material such as non-polar substrate that adopts is arisen at the historic moment, but does not also have the report of high-level efficiency LED to occur at present, and its inside still exists polarization effect, still has larger impact to the luminescence efficiency of LED.
In order to measure the polarized electric field of LED, having used for reference the method for a lot of GaAs system, as wavelength shift and component change calculations method, but having had higher dislocation desity due to GaN, its emission wavelength and component are also not exclusively corresponding, are difficult to Measurement accuracy.Therefore study the Accurate measurement of polarized electric field, the improved efficiency research of LED is had great importance.
Summary of the invention
(1) technical matters that will solve
Technical matters to be solved by this invention is that the accuracy of existing LED polarized electric field measuring method is not high, and the efficient studies be difficult to for LED provides support.
(2) technical scheme
The invention provides a kind of method utilizing photoluminescence spectrometry GaN base LED polarized electric field, comprise step S1: make GaN base LED and test sample, described test sample is lower supreme substrate, low temperature nucleation layer, low temperature buffer layer, n-layer, active area and the p-type layer of being followed successively by vain, and p-type layer and n-layer have p-electrode and n-electrode respectively; Step S2: utilize and test sample described in the complete irradiation of laser and measure its photocurrent exported and photovoltage; Step S3: connect positive voltage to the n-electrode of described test sample, p-electrode connects negative voltage, forms reverse biased; Step S4: the reverse biased equaling photovoltage is applied to described test sample, measures its photoluminescence spectrum, and record its emission wavelength, then substep increases reverse biased, and measure its spectrum and wavelength, when wavelength transferring to elongated by shortening gradually, stopping increasing reverse biased and stopping measuring; Step S5: utilize step S4 to stop reverse biased when measuring to deduct photovoltage that step S2 obtains obtains the polarizing voltage of described test sample, calculates the polarized electric field of test sample according to this polarizing voltage.
According to the preferred embodiment of the present invention, in step sl, the step utilizing GaN base LED to make test sample is: on described epitaxial wafer, choose a test zone, the side of test zone is etched, etching depth arrives the surface of n-layer, form a table top, and prepare n-electrode on this table top; Prepare p-electrode at the opposite side of test zone, make test sample.
According to the preferred embodiment of the present invention, harmonic lasers in described step S2, is adopted to produce described laser.
According to the preferred embodiment of the present invention, described step S3 carries out in the temperature environment of 10K ~ 450K.
According to the preferred embodiment of the present invention, in step S4, the step-length of substep is 1V.
According to the preferred embodiment of the present invention, in step s 5, according to the polarized electric field of following formulae discovery test sample: E=(U
1-U
0)/d, wherein, E is the electric field intensity of described polarized electric field, U
1for described step S4 stops reverse biased when measuring, U
0for the photovoltage that described step S2 obtains, d is the active area thickness of described test sample.
(3) beneficial effect
The present invention utilizes band curvature theoretical, becomes level and tilts, by the reverse biased balanced as polarizing voltage, and then calculate polarized electric field, symbolize the polarized electric field that LED internal polarization effect causes intuitively by the enable band of applying reverse biased from inclination.
Due to the fluctuation of In component in the lattice mismatch of InGaN and GaN and InGaN, the white hair of LED inside is caused to polarize and answer polarization to be difficult to direct measurement.The present invention, by directly measuring photoluminescence wavelength change under reverse bias, can calculate the polarized electric field of LED inside accurately.
The present invention is simple to sample requirement, and sample preparation is convenient, can obtain test result quickly, is conducive to meeting the active demand of producing and to test data in research and development technique.
Accompanying drawing explanation
Fig. 1 is the structural representation of GaN base LED;
Fig. 2 is the structural representation that GaN base LED of the present invention tests sample;
Fig. 3 is the structural representation of proving installation of the present invention;
Fig. 4 be to test sample apply reverse biased time can be with schematic diagram.
Embodiment
The present invention is from electric field balance angle, and the electric field formed by applying reverse biased to GaN base LED offsets the effect of its built-in polarized electric field, and theoretical according to band curvature, the wavelength variations in conjunction with GaN base LED measures the built-in polarized electric field of LED.
In practical application, LED both can be LED, and also can be LED chip, LED be commonly referred to as the full structured wafer of LED (Wafer), and by etching, thinning, evaporation, draw and split, obtain LED chip after the processes such as encapsulation.As shown in Figure 1, it is lower supreme substrate, low temperature nucleation layer, low temperature buffer layer, n-layer, active area and the p-type layer of being followed successively by vain, and wherein active area is double-heterostructure, single quantum or multi-quantum pit structure for the structure of GaN base LED.
Method of testing of the present invention comprises the steps:
Step S1: make GaN base LED and test sample, described test sample is lower supreme substrate, low temperature nucleation layer, low temperature buffer layer, n-layer, active area and the p-type layer of being followed successively by vain, and p-type layer and n-layer have p-electrode and n-electrode respectively.
For LED chip, when making test sample, only need the encapsulating material removing chip surface, make laser can direct projection sample.
For LED, first can choose a test zone on epitaxial wafer, etch the side of test zone, etching depth arrives the surface of n-layer, forms a table top, and prepare n-electrode on this table top; Prepare p-electrode at the opposite side of test zone, make test sample 2.The structure of the test sample made as shown in Figure 2.
Step S2: utilize and test sample described in the complete irradiation of laser and measure its photocurrent exported and photovoltage.Laser instrument is preferably corresponding harmonic lasers.
Step S3: connect positive voltage to the n-electrode of described test sample, p-electrode connects negative voltage, forms reverse biased.
This is executed biased step and realizes by a direct supply.This step can be carried out when 10K ~ 450K, preferably test sample is placed in low temperature environment, is conducive to confirmation and the reading of spectral wavelength like this.Preferred low temperature environment is 10K.Need under low temperature environment in addition to consider that resistance in series increases the factors such as the voltage rising introduced.If do not possess low temperature environment, the present invention at room temperature also can carry out.
Step S4: the reverse biased equaling photovoltage is applied to described test sample, measure its photoluminescence spectrum, and record its emission wavelength, then substep measures its spectrum and wavelength after increasing reverse biased, when wavelength is by when blue shift transfers red shift to gradually, stop increasing reverse biased and stop measuring.
As shown in Figure 4, measured the fluorescence spectrum under different bias voltage by the step-length of 1V respectively, its wavelength, can blue shift gradually along with the increase of reverse biased, and reverse biased now makes the band gap of LED become large, can be with become from inclination parallel; Can be with parallel after, along with the further increase of reverse biased, can be with to tilting in the other direction, band gap diminishes, and now wavelength starts red shift.
Step S5: utilize step S4 to stop reverse biased when measuring to deduct photovoltage that step S2 obtains obtains the polarizing voltage of described test sample, calculates the polarized electric field of this test sample according to this polarizing voltage.
According to flatband conditions, E=U/d, E are electric field intensity, and U is voltage between flat rubber belting, and d is active area thickness.
Step S4 stops reverse biased U when measuring
1deduct the polarizing voltage U that photovoltage is exactly LED sample
0, be voltage U between flat rubber belting.By above-mentioned formulae discovery, draw its polarized electric field E=U/d=(U
1-U
0)/d.
For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in further detail.
This embodiment is the polarized electric field of a test blue-ray LED, specifically comprises the steps:
Step S1: utilize metal-organic chemical vapor deposition equipment (MOCVD) or molecular beam epitaxy (MBE) growing GaN base LED epitaxial wafer, epitaxial wafer is blue light GaN base LED.As previously mentioned, its structure is followed successively by substrate, low temperature nucleation layer, low temperature buffer layer, n-layer, active area and p-type layer, and wherein active area is multi-quantum pit structure, and the number of Multiple Quantum Well is 9, and the thickness of trap is 3nm, and barrier layer thickness is 12nm.
Epitaxial wafer is chosen a test zone, and superincumbent side adopts ICP to etch, below the surface that etching depth arrives n-layer about 1 μm, form a table top, and utilize PECVD to prepare n-electrode thereon, prepare p-electrode at opposite side, and add lead-in wire, make test sample.This step also can adopt LED chip technique to make standard LED chip;
Step S2: will test sample and connect upper conductor, and be arranged on testing tool, instrumentation diagram as shown in Figure 3, utilizes the resonance complete irradiation sample of laser and measures corresponding photogenerated current and photovoltage with current voltmeter.
As shown in Figure 3, described testing tool comprises voltage source, monochromator, detector, laser instrument and temperature-controlling system etc.Be connected with test sample by voltage source, reverse biased is applied to sample; By laser instrument to test sample irradiation, produce fluorescence; Collection and the spectrum test of fluorescence is realized by monochromator and detector, and recording wavelength; Temperature-controlling system can realize the condition of different temperatures of test request.
Step S3: connect positive pole by a direct voltage source to test sample n-electrode, p-electrode connects negative pole, forms reverse biased; And realizing path, regulate spectral signal to reach maximum when not adding external bias voltage.In order to measure spectrum better, test sample is placed in 10K temperature by this embodiment.
Step S4: apply the reverse biased equaling photovoltage, measure its photoluminescence spectrum, and record its emission wavelength, then reverse biased is increased with the step-length of 1V, and measure its spectrum and wavelength, reduce step-length when wavelength transfers to elongated by shortening gradually and measure, until find final equilibrium point.
Step S5: reverse biased now deducts the polarizing voltage that photovoltage is exactly LED sample, is calculated by above-mentioned theory, draws its built-in polarized electric field.
Fig. 4 can be with schematic diagram when applying reverse biased to test sample, and wherein (a) figure is polarized electric field original state, and (b) figure balances afterwards state with reverse biased, (c) figure is the excessive rear state of reverse biased.Due to the lattice mismatch of InGaN and GaN, produce piezoelectric polarization in quantum well inside, cause being with inclination, as shown in (a), band gap diminishes, and after applying reverse biased to test sample, inhibits polarization effect, along with the increase of reverse biased, reverse biased and polarizing voltage are offset, now can be with become parallel, as shown in (b), and the continuation of reverse biased increases and can tilt, as shown in (c) to opposite direction by enable band.
In the present invention, Measurement accuracy balance reverse biased is the key of Measurement accuracy LED polarized electric field, by Measurement accuracy photovoltage and reverse biased, and reverse biased is deducted photovoltage as equilibrium polarisation voltage, improves test accuracy.
Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (6)
1. measure a method for GaN base LED polarized electric field, comprise the steps:
Step S1: make GaN base LED and test sample, described test sample is followed successively by substrate, low temperature nucleation layer, low temperature buffer layer, n-layer, active area and p-type layer from bottom to top, and p-type layer and n-layer have p-electrode and n-electrode respectively;
Step S2: utilize and test sample described in the complete irradiation of laser and measure its photocurrent exported and photovoltage;
Step S3: connect positive voltage to the n-electrode of described test sample, p-electrode connects negative voltage, forms reverse biased;
Step S4: the reverse biased equaling photovoltage is applied to described test sample, measures its photoluminescence spectrum, and record its emission wavelength, then substep increases reverse biased, and measure its spectrum and wavelength, when wavelength transferring to elongated by shortening gradually, stopping increasing reverse biased and stopping measuring;
Step S5: utilize step S4 to stop reverse biased when measuring to deduct photovoltage that step S2 obtains obtains the polarizing voltage of described test sample, calculates the polarized electric field of test sample according to this polarizing voltage.
2. the method for measurement GaN base LED polarized electric field according to claim 1, is characterized in that: in step sl, and the step making GaN base LED test sample is:
Described epitaxial wafer is chosen a test zone, etches the side of test zone, etching depth arrives the surface of n-layer, forms a table top, and prepare n-electrode on this table top;
Prepare p-electrode at the opposite side of test zone, make test sample.
3. the method for measurement GaN base LED polarized electric field according to claim 1, is characterized in that, adopts harmonic lasers to produce described laser in described step S2.
4. the method for measurement GaN base LED polarized electric field according to claim 1, is characterized in that, described step S3 carries out in the temperature environment of 10K ~ 450K.
5. the method for measurement GaN base LED polarized electric field according to claim 1, is characterized in that, in step S4, the step-length of substep is 1V.
6. the method for measurement GaN base LED polarized electric field according to claim 1, is characterized in that, in step s 5, and the polarized electric field according to following formulae discovery test sample:
E＝(U
1-U
0)/d，
Wherein, E is the electric field intensity of described polarized electric field, U
1for described step S4 stops reverse biased when measuring, U
0for the photovoltage that described step S2 obtains, d is the active area thickness of described test sample.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310459347.8A CN103529310B (en) | 2013-09-25 | 2013-09-25 | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310459347.8A CN103529310B (en) | 2013-09-25 | 2013-09-25 | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103529310A CN103529310A (en) | 2014-01-22 |
| CN103529310B true CN103529310B (en) | 2015-12-23 |
Family
ID=49931478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310459347.8A Active CN103529310B (en) | 2013-09-25 | 2013-09-25 | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103529310B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105606982B (en) * | 2015-09-11 | 2018-05-22 | 厦门市三安光电科技有限公司 | A kind of in-situ test system of iii-nitride light emitting devices magnetoelectricity stress coupling |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5572016A (en) * | 1995-04-25 | 1996-11-05 | Martin Marietta Corporation | Photoluminescence built-in-test for optically initiated systems |
| CN1776442A (en) * | 2005-11-23 | 2006-05-24 | 中国科学院上海技术物理研究所 | Method for detecting gallium nitride base LED quality good or not |
| CN1797795A (en) * | 2004-12-27 | 2006-07-05 | 北京大学 | Method for preparing LED chip with 2D natural scattered faces for outputting light |
| CN1801498A (en) * | 2005-01-07 | 2006-07-12 | 北京大学 | Method for preparing LED chip with separate crystal grain vertical structure |
| CN1881626A (en) * | 2005-06-14 | 2006-12-20 | 中国科学院半导体研究所 | Method for making GaN-based blue light light-emitting diode with photon microstructure |
| CN101339970A (en) * | 2007-07-03 | 2009-01-07 | 索尼株式会社 | Gallium nitride-based semiconductor element, optical device using the same, and image display apparatus using optical device |
| CN101807640A (en) * | 2010-03-05 | 2010-08-18 | 中国科学院半导体研究所 | Method for improving LED luminous efficiency by using three-dimensional polarized induction positive hole gas |
| CN102549781A (en) * | 2009-09-30 | 2012-07-04 | 住友电气工业株式会社 | Method for producing semiconductor light-emitting element |
| CN102709418A (en) * | 2012-07-16 | 2012-10-03 | 广东工业大学 | Spectrum adjustable zinc oxide (ZnO)/gallium nitride (GaN) based white light emitting device structure |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0423482A (en) * | 1990-05-18 | 1992-01-27 | Fujitsu Ltd | Method for appreciation of refractive index difference |
| JP3201655B2 (en) * | 1992-08-21 | 2001-08-27 | 浜松ホトニクス株式会社 | Electric field measurement device |
-
2013
- 2013-09-25 CN CN201310459347.8A patent/CN103529310B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5572016A (en) * | 1995-04-25 | 1996-11-05 | Martin Marietta Corporation | Photoluminescence built-in-test for optically initiated systems |
| CN1797795A (en) * | 2004-12-27 | 2006-07-05 | 北京大学 | Method for preparing LED chip with 2D natural scattered faces for outputting light |
| CN1801498A (en) * | 2005-01-07 | 2006-07-12 | 北京大学 | Method for preparing LED chip with separate crystal grain vertical structure |
| CN1881626A (en) * | 2005-06-14 | 2006-12-20 | 中国科学院半导体研究所 | Method for making GaN-based blue light light-emitting diode with photon microstructure |
| CN1776442A (en) * | 2005-11-23 | 2006-05-24 | 中国科学院上海技术物理研究所 | Method for detecting gallium nitride base LED quality good or not |
| CN101339970A (en) * | 2007-07-03 | 2009-01-07 | 索尼株式会社 | Gallium nitride-based semiconductor element, optical device using the same, and image display apparatus using optical device |
| CN102549781A (en) * | 2009-09-30 | 2012-07-04 | 住友电气工业株式会社 | Method for producing semiconductor light-emitting element |
| CN101807640A (en) * | 2010-03-05 | 2010-08-18 | 中国科学院半导体研究所 | Method for improving LED luminous efficiency by using three-dimensional polarized induction positive hole gas |
| CN102709418A (en) * | 2012-07-16 | 2012-10-03 | 广东工业大学 | Spectrum adjustable zinc oxide (ZnO)/gallium nitride (GaN) based white light emitting device structure |
Non-Patent Citations (1)
| Title |
|---|
| 基于电容和电导特性分析GaN蓝光发光二极管老化机理;陈焕庭等;《物理学报》;20090831;第58卷(第8期);第5700-5704页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103529310A (en) | 2014-01-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Grillot et al. | Sixty thousand hour light output reliability of AlGaInP light emitting diodes | |
| US8496353B2 (en) | Light-emitting diode (LED) module with light sensor configurations for optical feedback | |
| CN103528802B (en) | A kind of method utilizing electroluminescence spectrometry internal quantum efficiency of nitride | |
| Pralgauskaitė et al. | Reliability investigation of light-emitting diodes via low frequency noise characteristics | |
| CN102544276A (en) | Non-polar GaN thin film grown on LiGaO2 substrate, as well as manufacturing method and application thereof | |
| CN103529310B (en) | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED | |
| Islam et al. | Generation of sidewall defects in InGaN/GaN blue micro-LEDs under forward-current stress | |
| Sabbar et al. | Systematic investigation of spontaneous emission quantum efficiency drop up to 800 K for future power electronics applications | |
| Park et al. | Recent advances in micro-pixel light emitting diode technology | |
| Zhou et al. | Enhancement in light extraction of LEDs with SiO2 current blocking layer deposited on naturally textured p-GaN surface | |
| CN209689771U (en) | A kind of temperature measuring device | |
| US20190081208A1 (en) | Light emitting device and light emitting device package including the same | |
| Li et al. | In-situ measurement of junction temperature and light intensity of light emitting diodes with an internal sensor unit | |
| CN109855750A (en) | A kind of temperature measuring device and measurement method | |
| Kim et al. | Effects of carrier leakage on photoluminescence properties of GaN-based light-emitting diodes at room temperature | |
| Zhu et al. | Demonstration of GaN-based white LED grown on 4-inch patterned sapphire substrate by MOCVD | |
| US20150323463A1 (en) | Method and device for measuring internal quantum efficiency of an optical element | |
| CN209689770U (en) | A kind of temperature measuring device | |
| Li et al. | 29‐3: Exploring the Temperature Dependence of GaN‐on‐GaN Homoepitaxy Micro‐LEDs | |
| CN202454605U (en) | Nonpolar GaN film growing on LiGao2 substrate | |
| Li et al. | High-speed micro-LEDs based on nano-engineered InGaN active region towards chip-to-chip interconnections | |
| Raymond et al. | Photoluminescence metrology for LED characterization in high volume manufacturing | |
| Kim et al. | MSM photodetector on a polysilicon membrane for a silicon-based wafer-level packaged LED | |
| Meneghini et al. | Failure mechanisms of gallium nitride LEDs related with passivation | |
| Luan et al. | Research on influencing factors of LED frequency response |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |