JPS62140474A - Manufacture of photoelectric conversion device - Google Patents

Abstract

PURPOSE:To form a thin-film body having light transmission by including a specific quantity or less of a perovskite type oxide in the oxide of a specific quantity of lead and chromium and using the mixture as a target. CONSTITUTION:Oxides containing not more than 95mol% perovskite type oxide to the composition of lead of 30-99.5mol% calculated in terms of PbO and chromium of 0.5-70mol% calculated in terms of Cr2O3 are employed as a target, and a thin-film consisting of the oxides containing lead and chromium is shaped in a vacuum. The thin-film is thermally treated in an atmosphere including at least lead. Photoelectromotive force is hardly generated on a thin- film composed of not less than 99.5mol% PbO and on a thin-film made up of not less than 70mol% Cr2O3. Likewise, electromotive force is hardly generated even on a thin-film consisting of not less than 95mol% PbTiO3. Accordingly, the thin-film having light transmission is acquired, thus improving the conversion efficiency of the operation of a photoelectric conversion device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a photoelectric conversion device constituted by a thin film of an oxide containing lead and chromium.

[Technical background of the invention and its problems] As charging conversion devices, photoelectric conversion devices using junctions of P-n or P-n-P conductivity type semiconductors, or junctions between semiconductors and metals are widely used. It is well known that These photoelectric conversion devices generate their own electromotive force when exposed to light, so there is no need for an external electromotive force.

In addition, the applicant discovered the photoelectric conversion phenomenon of dielectric materials in the process of researching oxide dielectric materials without using the above-mentioned junctions, and discovered that oxides containing lead and chromium A patent application was filed in 1983 for a charging conversion device formed by forming a conductive layer.
-91295 (Japanese Patent Application No. 55-17969). According to this photoelectric conversion device, light incident on the oxide is converted into an electric current within the oxide, and is extracted to the outside of the photoelectric conversion device through the conductive layer. When this oxide was a thin film, it generated an electromotive force in response to incident light and exhibited photosensitivity, and when the oxide was thick, it exhibited an electricity storage effect.

By the way, the method for manufacturing a photoelectric conversion device shown in this application involves mixing lead oxide and chromium oxide, sintering them to form a sintered body, and forming a conductive layer on this sintered body. ing.

However, when forming a thin film of dielectric material by such a sintering method, there is a limit to its thickness, and there are also problems in that it is difficult to form a uniform thin film with few pores. Furthermore, since this thin film body does not have light transmittance, it is not possible to increase the conversion efficiency when applied to various photoelectric conversion devices.

[Object of the Invention] An object of the present invention is to provide a method for manufacturing a photoelectric conversion device that enables the formation of a thin film body having optical transparency.

[Summary of the Invention] The present invention for achieving the above-mentioned object has the following advantages: 30 to 99.5 mo! of lead in terms of PbO! % and chromium in terms of Cr2O3 and a composition of 0.5 to 70 mol%, a thin film of the above-mentioned oxide containing lead and chromium is prepared in vacuum using an oxide containing 95m01% or less of perovskite type oxide as a target. This thin film is then heat-treated in an atmosphere containing at least lead.

[Embodiments of the invention] The present invention will be explained in detail below.

Example 1 PbT as a perovskite oxide was added to the composition of Pb2CrO5 using lead sulfuride Pbo, chromium oxide Cr203 and titanium oxide Ti02 as starting materials.
It was weighed so that the composition contained 10 mo+% of iO3. These raw materials were wet mixed in a polyethylene pot for 10 to 15 hours, dried, and then pre-calcined at 400 to 500°C for 2 hours. 10-15 in ball mill after pre-firing
Pulverization was performed for a period of time to obtain a particle size of approximately 1 μm. A binder was added to this calcined powder, and the powder was press-molded at 1 torrl/cm.

Furthermore, the molded body was fired at 650 to 900'C for 2 hours to obtain a sintered body.

Next, using a sintered body in which 10 m01 of PbTiO3, which is a perovskite type oxide, was added to the component consisting of Pb2CrO5 as a target (evaporation source), PbzC was deposited on a glass substrate by the electron beam evaporation method as follows.
A thin film of r06 was formed.

That is, the above Pb is placed inside the vacuum chamber of the electron beam evaporation device.
PbzCrOs sintered body containing TiO3 with a diameter of 15.6 m
A disk-shaped target with a thickness of 3.0M and a glass substrate were arranged, and the vacuum degree in the container was 1X with the accelerating voltage of a 350'C1 electron gun maintained at 4kV.
Deposition started when 10-7 Torr was reached. By setting the deposition time to about 1 to 2 hours, a thin film of Pb2CrO5 with a thickness of 0.5 to 1.5 μm was formed on the glass substrate. The degree of vacuum during vapor deposition was 4 x 10-5 Torr.
I arrived at r.

Next, in this way (the suspended glass substrate was
Heat treatment was performed at 450'C for 1.5 hours in an atmosphere where the r○5 sintered powder was held in an aluminum crucible. Amorphous Pb2c is deposited by electron beam through this heat treatment.
The ro5 thin film is crystallized. Pbz Crys powder is used to prevent Pb component separation from the Pb2CrOsi film.

The obtained Pb2CrO5 thin sample exhibits an orange color, and the first
Transmission characteristics A and reflection characteristics B are shown as shown in the figure.

The horizontal axis shows the wavelength (A>) of the reflected light, and the Pa axis shows the transmittance and reflectance (%).

Here, the transmission characteristic A is a unique characteristic obtained by the present invention, and such a transmission characteristic cannot be obtained with a conventional sintered body.

Subsequently, a pair of conductive layers 1 and 2 having the pattern and dimensions as shown in FIG. 2, which serve as an electric source, were formed on the Pb2CrO5 thin film by vacuum evaporating gold. by this,
A photoelectric conversion device composed of a glass substrate, a Pb2CrO5 thin film, and a gold layer is obtained. By measuring the photovoltaic force of this photoelectric conversion device using a measuring device as shown in FIG. 3, characteristics as shown in FIGS. 4 and 5 were obtained.

In FIG. 3, 3 is a light source, 4 is a chopper, 5 is a monochromator, 6 is a sample, 7 is a pen recorder, and 8 is a measuring circuit. In Figures 4 and 5, the horizontal axis is time (minutes) and light intensity (mW/Cd), and the vertical axis is photovoltaic force (V
) is shown.

Figure 4 shows the photovoltaic force characteristics when the light irradiated to the photoelectric conversion device is turned on and off. When it is turned on, the photovoltaic force increases from 0, and when it is turned off, the photovoltaic force increases from 0. decrease in the direction. That is, by turning the light on and off, photovoltaic force can be generated or eliminated.

FIG. 5 shows the photovoltaic force characteristics when the intensity of light irradiated to the photoelectric conversion device is changed, and the photovoltaic force increases in proportion to the intensity of light.

If the characteristics of the present invention as shown in Figs. 1, 4, and 5 are applied to photovoltaic elements, optical sensor elements, etc., the conversion efficiency of the element operation can be increased by utilizing the light transmittance. be able to. This is true whether the light receiving section is of a transmissive type or a reflective type. These functions and effects are based on the fact that according to the present invention, a Pb2CrO5 thin film body having light transmittance can be formed. Moreover, a uniform thin film with almost no pores can be formed.

Example 2 Pb was deposited on a glass substrate at the same composition ratio and under the same conditions as Example 1.
A 2CrO5 thin film was formed. Next, the glass substrate thus obtained was heat treated under different temperature conditions, and a pair of conductive layers were formed under the same conditions to form a photoelectric conversion device.

When the photosensitivity of the obtained photoelectric conversion device was measured, it was confirmed that photosensitivity could not be obtained when the heat treatment temperature was 150° or less.

Example 3 Two types of components having compositions of Pb5Cro8 and PbCrO4 were prepared using the same starting materials as in Example 1, and 1Qmol% of PbTiO3 was added to each to form two types of sintered bodies. Next, using these as targets, a Pbs Cr'Oe thin film and a PbCrO4 thin film were respectively formed, followed by heat treatment and formation of a conductive layer to form two types of photoelectric conversion devices. It was confirmed that photosensitivity could be obtained in any of the photoelectric conversion devices. Other perovskite-type oxides include PbZrO3 and Pb(Co1/2N
It was confirmed that a material having a composition of b1/2>03 can be used and results similar to those of PbTiO3 can be obtained.

Example 4 Similar to Example 1, PbO and Cr2O3 were used as starting materials, and the components were mixed by sequentially changing the ratio of the two,
Sintered bodies of chromium lead with various composition ratios to which PbTiO3 was added were formed. Using these as targets, various lead chromate thin films were formed, and after heat treatment, conductive layers were formed to form multiple types of photoelectric conversion devices. When the photovoltaic characteristics of these photoelectric conversion devices were measured, the following results were obtained.

That is, in the case of a thin film containing PbO of 99.5 mol % or more and in the case of a thin film containing 70 mol % or more of Cr2O3, almost no photovoltaic force was generated. Similarly, PbTiO3
Almost no electromotive force was generated even in the case of a thin film with a concentration of 95 mol % or more. In addition, in the composition ratio of PbO and Cr2O3, if Cr2O3 is in excess of PbCrO4, P
It was confirmed that a mixed crystal of bCrO4 and Cr203 was formed and existed. Similarly, PbCrO4 is
When bO is excessive, a mixed crystal of Pb5CrOB and PbO is formed, and in the intermediate region, PbO and Cr203 are formed.

Pb2Crys, Pb5Crys, PbCrO4P
It was confirmed that some combination of mixed crystals of bTiO3 and T i 02 existed.

Furthermore, Pb2CrO5 is immersed in photovoltaic properties.
, PbsCrys, a single oxide of PbCrO4, and a thin film close to a mixed crystal of PbTiO3.

In each of the above embodiments, the method for forming an oxide containing lead and chromium, such as Pb2CrO5 to which a perovskite oxide is added, has been described using electron beam evaporation as an example, but is not limited to this. Alternatively, a method for forming a thin film in a vacuum such as sputtering or ion beam evaporation can be used, and similar effects and effects can be obtained by these methods. Furthermore, although gold has been described as an example of the material for the conductive layer, other materials such as aluminum and copper can also be used.

The substrate on which the thin film is to be formed is not limited to glass, and other materials can be selected. By forming a thin film on a substrate in this manner, a photoelectric conversion device having a uniform thin film with few pores can be obtained without being restricted by the thickness of the thin film body including the substrate.

[Effects of the Invention] As explained above, according to the present invention, a thin film of an oxide containing lead and chromium to which a perovskite oxide is added is formed in vacuum, and then this thin film is heat-treated. As a result, the following effects can be obtained.

(1) Since a thin film having optical transparency can be obtained, the conversion efficiency of the photoelectric conversion device can be improved.

('2J) Since a uniform thin film with almost no pores can be formed, a high quality and highly reliable photoelectric conversion device can be obtained.

(3) Since mass production is possible through the use of vacuum technology, photoelectric conversion devices can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the transmittance and reflectance of a photoelectric conversion device obtained by an example of the present invention, FIG. 2 is a pattern diagram showing electrodes of a photoelectric conversion device obtained by an example of the present invention, and FIG. 4 and 5 are characteristic diagrams showing the photoelectromotive force of the photoelectric conversion device obtained according to the embodiment of the present invention. FIGS. 1.2... Conductive layer, 3... Light source, 4... Chopper, 5... Monochromator, 6... Sample, 7...
Pen coder, 8... measurement circuit.

Claims (5)

[Claims] (1) 30 to 99.5 mol% of lead converted to PbO and 0.5 to 70 mol% of chromium converted to Cr_2O_3
perovskite type oxide for a composition of 1%.
Forming a thin film of the oxide containing lead and chromium in a vacuum using an oxide containing 0.1% or less as a target,
A method for manufacturing a photoelectric conversion device, which comprises then heat-treating this thin film in an atmosphere containing at least lead. (2) The method for manufacturing a photoelectric conversion device according to claim 1, characterized in that the thin film of the oxide containing lead and chromium is formed on a glass substrate. (3) A pair of conductive layers are formed on a thin film of an oxide containing lead and chromium.
A method for manufacturing a photoelectric conversion device according to section 1. (4) PbTiO_ as the perovskite oxide
3. The method for manufacturing a photoelectric conversion device according to claim 1, wherein at least one of PbZrO_3 and PbZrO_3 is used. (5) The method for manufacturing a photoelectric conversion device according to claim 1, characterized in that a sintered ceramic plate formed in a plate shape is used as the oxide.