JPS63208056A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body which has a high traveling property of a carrier and has high resistance and excellent electric charge characteristic by using the superlattice structure constituted by laminating thin layers having optical band gaps different from each other on a photoconductive layer. CONSTITUTION:The photoconductive layer 3 is constituted of an electric charge generating layer 6 and an electric charge holding layer 5. The charge holding layer 5 is constituted by alternately laminating thin fine crystalline silicon films and thin amorphous silicon films contg. elements for increasing dark resistance. The charge generating layer 6 is constituted by alternately laminating two fine crystalline silicon films at least one of which contains an element for increasing dark resistance. The concns. of the elements for increasing the dark resistance in the thin fine crystalline silicon films are changed with each of the thin films in the layer thickness direction. The elements for increasing the dark resistance includes, for example, carbon, oxygen, nitrogen, hydrogen, etc. These thin films vary in the optical band gaps and the respective thicknesses thereof are in a 30-200Angstrom range. The excellent traveling property of the carrier and high photoconductive characteristics are thereby obtd. and a sharper image is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor having excellent charging characteristics, dark decay characteristics, photosensitivity characteristics, environmental resistance, and the like.

[Prior art] Amorphous silicon (hereinafter referred to as a) containing hydrogen (H)
-8t:, abbreviated as H) has recently attracted attention as a photoelectric conversion material, and has been applied to photoreceptors in electrophotographic processes as well as solar cells, thin film transistors, image sensors, etc.

Conventionally, materials constituting the photoconductive layer of electrophotographic photoreceptors include inorganic materials such as CdS, ZnO, Se, or 5e-Te, or poly(IJ + N-vinylcarbaso A/
(PVCz) or trinitrofluorenone (TNF
) and other organic materials were used. However, a-
8t:H is a non-polluting substance compared to these inorganic or organic materials, so there is no need for recovery treatment, and it is visible.
It has advantages such as "If, If, area photosensitivity, high surface hardness, and excellent wear resistance and impact resistance. Therefore, a-Si:H is suitable for electrophotography. It is attracting attention as a photoreceptor material for process.

This a-8t:H is being studied as a photoreceptor material based on the Carlnon method, but in this case, high resistance and photosensitivity are required as photoreceptor characteristics. However, it is difficult to satisfy both of these characteristics with a single photoreceptor, so a barrier layer is provided between the photoconductive layer and the conductive support, and a surface charge retention layer is provided on the photoconductive layer. These requirements are satisfied by providing a laminated structure.

[Problems to be Solved by the Invention] By the way, a-8t:H is usually formed by a glow discharge decomposition method using a silane gas, but at this time, hydrogen is not present in the a-8l:H layer. is incorporated, and the electrical and optical properties vary greatly due to the difference in the amount of hydrogen. That is,
As the amount of hydrogen that enters the a-8l:H film increases, the optical band gear increases and the resistance of a-8t:H increases, but as a result, the photosensitivity to long wavelength light decreases. Therefore, it is difficult to use it in, for example, a Radbeam printer equipped with a semiconductor laser.

Moreover, when the hydrogen content in the a-Sl:H layer increases,
Depending on the film forming conditions, those having bonding structures such as (SiF2)n and SiH2 may occupy most of the area in the film. In this case, voids increase and silicon dangling bonds increase, resulting in deterioration of photoconductive properties and rendering the material unusable as an electrophotographic photoreceptor. On the contrary, a-8
As the amount of hydrogen incorporated into t:H decreases, the optical band gap decreases and its resistance decreases;
Increased photosensitivity to long wavelength light. However, when the hydrogen content is low, there is less hydrogen to combine with and reduce the dangling bonds of silicon. For this reason,
The mobility of the generated carriers is lowered, the life is shortened, and the photoconductive properties are deteriorated, making it difficult to use as an electrophotographic photoreceptor.

In this way, the light guide of the electrophotographic photoreceptor can be layered into a single a-8
If the structure is made up of only the t:H layer, there is a problem that the characteristics change greatly depending on the manufacturing conditions of the a-81:H layer, and desired characteristics cannot be obtained.

The present invention has been made in view of such circumstances, and
To provide an electrophotographic photoreceptor that has excellent charging ability, low residual potential, high photosensitivity over a wide wavelength range up to the near infrared region, good adhesion to a substrate, and excellent environmental resistance. With the goal.

[Structure of the Invention] (Means for Solving the Problems) As a result of various studies, the present inventors discovered that the photoconductive layer of an electrophotographic photoreceptor is composed of a 't-m charge retention layer and a charge generation layer. However, the present inventors have discovered that the above object can be achieved by stacking a plurality of predetermined semiconductor films, that is, forming a region with a superlattice structure, and have completed the present invention.

That is, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor comprising an electrically conductive support and a photoconductive layer, the photoconductive layer comprising a charge generation layer and a charge retention layer, The holding layer is formed by alternately laminating microcrystalline silicon thin films and amorphous silicon thin films containing an element that increases dark resistance, and the 'd charge generation layer, at least one of which contains an element that increases dark resistance. The microcrystalline silicon thin film is constructed by alternately stacking two microcrystalline silicon thin films, and is characterized in that the concentration of the element that increases the dark resistance in the microcrystalline silicon thin film varies from film to film in the layer thickness direction.

Examples of elements included in the thin film that increase dark resistance include carbon, oxygen, nitrogen, and hydrogen.

The microcrystalline silicon (μc-8L) used in the present invention is thought to be formed from a mixed layer of microcrystalline silicon and amorphous silicon with a grain size of about several tens of angstroms, and the following: It has the following physical properties.

First, X-ray diffraction measurements show a crystal diffraction mother turn with 2θ around 28 to 2.8.5', which is clearly distinguishable from amorphous a-8t in which only a halo appears. Second, μ
The dark resistance of e-8i can be adjusted to 10 10 Ω·σ or more, and it is clearly distinguished from polycrystalline silicon, which has a dark resistance of 10 5 Ω·m.

The optical bandgap (Eg') of the μc-9l used in the present invention is preferably 1.55 eV, for example. However, it can be set arbitrarily within a certain range. Preferably, the required amount of hydrogen is added to each to obtain the desired EgO and used as μc-81:H. This compensates for silicon dangling, balances dark resistance and bright resistance, and improves jt and conductive properties.

Note that actual μe-si# often takes on a weak P-type or N-type depending on specific factors such as manufacturing conditions (especially tends to be an N-type). Therefore, in order to obtain the type 1 required to form a superlattice structure, it is desirable to lightly dope impurities having opposite conductivity types to cancel out the P type or N type.

The concentration of the element that increases dark resistance contained in the thin film is preferably 0.01 to 20 atoms, more preferably 0.5 to 1
0 atoms, and in a microcrystalline silicon # film, it can be varied within that range.

The thickness of each thin film constituting the superlattice structure is 30 to 200X
It is preferable that

(Function) In the electrophotographic photoreceptor of the present invention, since the superlattice structure is provided in the layer of light 4', the lifetime of carriers generated in this region is long and the mobility is also high. Although the theory has not yet been fully established, there is no doubt that this is a quantum effect due to the periodic well potential characteristic of the superlattice structure, and this is particularly referred to as the superlattice effect.

In this way, the mobility of carriers in the photoconductive layer is large.
Furthermore, the sensitivity of the photoreceptor is significantly improved due to the longer life of the carrier.

(Example) FIG. 1 is a diagram showing a cross-sectional structure of an electrophotographic photoreceptor according to an example of the present invention. In the figure, a barrier layer 2 is formed on a conductive support 1, and a photoconductive layer 3 consisting of a charge retention layer 5 and a charge generation layer 6 is formed thereon. Further, a surface layer 4 is formed on the charge generation layer 6. Note that both the charge retention layer 5 and the charge generation layer 6 have a superlattice structure.

Hereinafter, the structure of the electrophotographic photoreceptor shown in FIG. 1 will be explained in detail.

The conductive support 1 usually consists of a drum made of aluminum.

The barrier layer 2 may be formed using μc-St or a-8t:H, or may be formed using a-BN:H (amorphous boron to which nitrogen and hydrogen are added). Furthermore, an insulating film may be used. For example, μc-8l:H and a-8
1:) A high-resistance insulating barrier layer can be formed by making I contain one or more elements selected from carbon, C, nitrogen, N, and oxygen. The thickness of barrier layer 2 is 10
0x to 10 μm is preferred.

The barrier layer 2 is formed into a round shape that enhances the charge retention function of the photoreceptor surface by suppressing the flow of charges between the conductive support 1 and the charge generation layer 5, thereby increasing the charging ability of the photoreceptor. It is something. Therefore, when a Carlson type photoreceptor is constructed using a semiconductor layer as a barrier layer, the barrier layer 2 is made to be P type or N type in order not to reduce the ability to retain charges charged on the surface. That is, when the surface of the photoreceptor is positively charged, the barrier layer 2 is made of P type to prevent electrons that neutralize the surface charge from being injected into the charge generation layer.

Conversely, when the surface is negatively charged, the barrier layer 2 is made of N type,
This prevents holes that neutralize surface charges from being injected into the charge generation layer. Since carriers injected from the barrier layer 2 become noise with respect to carriers generated in the charge generation layer 6 upon incidence of light, preventing carrier injection as described above improves sensitivity. In addition, pc-8t:H
and a-81: In order to make H type P,
It is preferable to dope with elements belonging to the group B1 aluminum At, gallium Ga, indium In, and thallium TA. Also, μc-8t:H
In order to make H or a-8i:N type, it is preferable to dope it with an element belonging to Group V of the periodic table, such as nitrogen, phosphorus P, arsenic As, antimony Sb, and bismuth Bi.

'The charge generation layer 6 generates carriers upon incidence of light,
One polarity of these charges neutralizes the charges on the surface of the photoreceptor, and the other one travels within the charge retention layer 5 and reaches the conductive support 1.

The charge retention layer 5 and the charge generation layer 6 are constructed by alternately laminating thin layers of two glazes. These thin layers have different optical bandgaps and each have a thickness in the range of 30-200X. In this way, by laminating mutually different thin layers in the optical band ear, a layer with a large optical band gap can be created based on a layer with a small optical band gap, regardless of the size of the optical band gap itself. A superlattice structure having a periodic potential barrier acting as a barrier is formed. In this superlattice structure,
Since the thin barrier layer is extremely thin, the carrier tunneling effect in the thin layer causes the carriers to travel through the barrier and into the superlattice structure.

Furthermore, in such a superlattice structure, a large number of carriers are generated due to original incidence. Therefore, it has high photosensitivity. Note that by changing the bandgap and layer thickness of the thin layer having the superlattice structure, the apparent bandgap of the layer having the heterojunction superlattice structure can be freely adjusted.

a-Sl forming the charge retention layer 5 and the charge generation layer 6
The hydrogen content in :H and μe-8t:H is
It is preferably 0.01 to 30 atoms, more preferably 1 to 25 atoms. Such hydrogen content compensates for silicon dangling, brings the dark resistance and bright resistance into balance, and improves the photoconductive properties.

a-8t: To simulate the H layer by the glow discharge decomposition method, silane gases such as SiH4 and 512H5 are introduced into the reaction chamber as raw materials, and H is produced in the thin layer by glow discharge using high frequency. Can be added.

If necessary, hydrogen or helium gas can be used as a carrier gas for the silanes.

On the other hand, silicon halides such as SiF4 gas and 5iCA4 gas can be used as the source gas. Furthermore, a-8i:H containing H can be similarly formed by reacting with a mixed gas of silane gas and silicon halide gas. In addition, regardless of the glow discharge decomposition method,
For example, these thin layers can also be formed by physical methods such as spacing and taring.

Similarly to a-3t:H, the μc-81 layer can also be formed using silane gas as a raw material by the high-frequency glow discharge decomposition method. In this case, the temperature of the support is a −St
:H is set higher than in the case of forming a-8i:H, and the high frequency power is also set higher than in the case of a-8i:H, μc-8t
:H becomes easier to form. Furthermore, by increasing the support temperature and high frequency power, the flow rate of source gas such as silane gas can be increased, and as a result, the film formation rate can be increased. Further, by using a gas obtained by diluting high-order silane gas such as 5t) I4 and S1□H6 with hydrogen, μc-8t:H can be formed with high efficiency.

In order to make μc-8t:H and a-8i:H P-type, an element belonging to Group Ⅰ of the periodic table, such as boron B,
Aluminum At, gallium Ga, indium In,
It is preferable to dope with thallium TL and the like,
In order to make Ac-8i:H and a-81:H n-type, elements belonging to Group Ⅰ of the periodic table, such as nitrogen N, phosphorus P, arsenic AI1. antimony sb and bismuth B1
It is preferable to dope. This doping with p-type impurities or nfi impurities prevents charges from moving from the support side to the photoconductive layer. On the other hand, μa−
By incorporating at least one element selected from carbon C9 nitrogen N and oxygen O into 8t:H and a-8L=H, high resistance can be achieved and the surface charge retention ability can be increased. The content of these elements is 5 to 40 atoms, preferably 10 to 30 atoms.

A surface layer 4 is provided on the charge generation layer 6.

Since the a-3l:H and the like of the charge generation layer 6 has a relatively large refractive index of 3 to 3.4, light reflection easily occurs on the surface. When such light reflection occurs, the proportion of the amount of light absorbed by the photoconductive layer or the charge generation layer decreases, resulting in increased light loss. For this reason, it is preferable to provide a superficial layer 4 to prevent reflection. In addition, by providing one surface layer 4,
Charge generation layer 6 is protected from damage. In addition, by forming the surface no, Obi'I! The hQ is improved, and the charge is better placed on the surface. Materials forming the surface layer include a-8iN:H, a-8iO:H, and a-
SIC: There are inorganic compounds such as H and organic materials such as polyvinyl chloride and polyamide.

When the surface of the electrophotographic photoreceptor constructed in this manner is charged with a positive voltage of about 500 V by corona discharge, an I-tension pariah is formed. When light (hv) is incident on this photoreceptor, carriers of electrons and holes are generated in the superlattice structure of the charge generation layer 6. Electrons in the conduction band are accelerated toward the surface layer 4 side by the electric field in the photoreceptor, and holes are accelerated toward the isoelectric support 15I11. In this case,
The number of carriers generated at the boundary between thin layers with different optical bandgaps is much larger than the number of carriers generated at the boundary. Therefore, in this superlattice structure,
High light sensitivity. Furthermore, in the potential well layer, due to quantum effects, the lifetime of carriers is 5 to 10 times longer than in the case of a single layer without a superlattice structure. Furthermore,
In a superlattice structure, a periodic barrier layer is formed due to bandgap discontinuity, but carriers easily pass through the bias layer due to the tunnel effect, so the effective carrier mobility is equivalent to that in the bulk. and
The carrier has excellent running performance.

Similarly, in the case of the charge retention layer 5, due to quantum effects, the lifetime of carriers in the potential well layer is 5 to 10 times longer than in the case of a single layer without a superlattice structure.

In addition, in a superlattice structure, a periodic barrier layer is formed due to bandgap discontinuity, but carriers easily pass through the bias layer due to the tunnel effect.
The effective mobility of the carrier is equivalent to the mobility in bulk, and the carrier has excellent mobility. As mentioned above,
A superlattice structure in which thin layers of different optical band gears are laminated allows high photoconductivity to be obtained and clear images to be obtained even with conventional photoreceptors.

Referring to FIG. 2, an apparatus and a manufacturing method for manufacturing the electrophotographic photoreceptor of the above embodiment by a glow discharge method will be described below. In the same figure, Gas Genpe 21, 22, 23.
24, for example, 5IH4°B2H6s H2*
A raw material gas such as CHa is contained.

These gases in Smenpe are supplied by pulp 26 for flow rate adjustment.
and is supplied to a mixer 28 via a pipe 27. A pressure gauge 25 is installed in each denpe,
By adjusting the valve 26 while monitoring the pressure gauge 25, the flow rate and mixing ratio of each source gas to be supplied to the mixer 28 can be adjusted.

The gases mixed in the mixer 28 are supplied to a reaction vessel 29. A rotating shaft 30 is attached to the bottom 31 of the reaction vessel 29 so as to be rotatable in a vertical direction. The rotating shaft 3
At the upper end of 0, a disk-shaped support 32 has its surface aligned with the rotation axis 30.
It is fixed vertically. Inside the reaction vessel 29, a cylindrical electrode 33 is installed on the bottom 31 with its axial center aligned with the axial center of the rotating shaft 30. A drum base 34 of the photoreceptor is placed on the support base 32 with its axial center aligned with the axial center of the rotating shaft 3°.
A heater 35 for heating the drum base is disposed inside the drum. A high frequency power source 36 is connected between the electrode 33 and the drum base 34, and one pole 33 and the drum base 34
A high frequency current is supplied between them. The rotating shaft 30 is rotationally driven by a motor 38. Reaction container 29
The internal pressure is monitored by a pressure gauge 37, and the reaction vessel 29 is connected via a Y-tonop valve 38 to a suitable exhaust means such as a nitrogen pump.

When manufacturing a photoreceptor using the above manufacturing apparatus, after installing the drum base 34 in the reaction container 29, the drum 39 is opened and the inside of the reaction container 29 is set to about 0, I To
Evacuate to a pressure below rr. Next? Npe 21.22
, 23 and 24, the required reaction gases are mixed at a predetermined mixing ratio and introduced into the reaction vessel 29.

In this case, the flow rate of the gas introduced into the reaction container 29 is such that the pressure inside the reaction container 29 ranges from 0.1 to 1. Set it to OTorr. Next, the motor 38 is operated to rotate the drum base 34, and the heater 35 rotates the drum base 34.
4 is heated to a constant temperature, and a source 36 of high frequency 'r is applied to form a high frequency film between the stain electrode 3 and the drum base 34, thereby forming a glow discharge between the two. As a result, a-8i:H is deposited on the drum base 34. In addition,
N20#NH3#N02#N2#CfI4 in raw material gas
By using #C2H410□ gas etc., carbon,
Oxygen and nitrogen can be included in a-8l:H.

As described above, the electrophotographic photoreceptor according to the present invention can be manufactured using a closed system manufacturing apparatus, and therefore is safe for the human body.

Next, the results of testing the electrophotographic properties of an electrophotographic photoreceptor according to the present invention formed into a film will be described.

Test Example 1 If necessary, to prevent interference, an aluminum drum base with a diameter of 80 m and a width of 350 strips, which has been subjected to acid treatment, alkali treatment, and sandblasting treatment, is installed in the reaction vessel. The vacuum was evacuated to approximately 10-5 torr.

While heating the drum base to 250°C and rotating it at 10 rpm, SiH4 gas was heated at 500 SCCM, B2H.
6 gas'(il'' 10 in flow rate ratio to SiH4 gas
It was introduced into the reaction vessel at a flow rate of 1 Torr, and the pressure inside the reaction vessel was reduced to 1 Torr. It was 4 verses. And 13.
Plasma is generated by applying high frequency power of 56 MHz, and a p-type JL-SIC:H barrier J- is placed on the drum base.
was formed.

Next, SIH4 gas was introduced into the reaction vessel at a flow rate of 500 SCCM, H2 gas was 250 SCCM, and CH4 gas was 30 SCCM), and 400 W of high-frequency power was applied to form a 120X a-3iC:H thin layer. did. Next, 50 SCCM of 5IH4 gas and 50 SCCM of H2 gas.
The reaction vessel was introduced at a flow rate of 0.008 CCM, the pressure inside the reaction vessel was set to 1.2 Tart, and a high frequency power of 1.2 kW was applied to form a 120× μc-8i:H thin conversion.

These operations were repeated to form a charge retention layer having a superlattice structure of 12 μm.

Next, 50 SCCM of SiH4 gas and 5 SCCM of H2 gas
The mixture was introduced at a flow rate of 00 SCCM, the pressure inside the reaction vessel was set to ITorr, and 1.2 kWO high frequency power was applied.
A 100X μc-8t:H thin layer was formed. Next, 2 SCCM of CH4 gas was further introduced to form a 100X μc-8 ICS H thin layer in the same manner. These operations were repeated to form a charge generation layer having a superlattice structure of 3 μm.

In addition, when forming the μa-81CSH thin layer, the flow rate of CH4 gas was increased for each thin layer, and the final
．． The carbon concentration was changed from 0.5 atoms to 4 atoms.

Finally, a surface layer consisting of a 0.1 μm a-8LC:H thin layer was formed.

When the surface of the photoreceptor thus formed is positively charged at about 500 V and exposed to white light, this light is absorbed by the charge generation layer and carriers of electron-hole pairs are generated. In this test example, a large number of carriers were generated, the carriers had a long life, and high running performance was obtained. This resulted in clear, high-quality images. Furthermore, when the photoreceptor manufactured in this test example was repeatedly charged, the reproducibility and stability of the transferred image were extremely good, and the corona resistance was also excellent.

It has been demonstrated that it has excellent durability such as moisture resistance and abrasion resistance.

The photoreceptor manufactured in this manner has high sensitivity even to long wavelength light of 780 to 790 nm, which is the oscillation wavelength of a semiconductor laser. When this photoreceptor was mounted on a semiconductor radar printer and an image was formed by a curling process, a clear, high-resolution image could be obtained even when the exposure amount on the surface of the photoreceptor was 25srgcn1.

Test Example 2 μC-8IC, one of the thin films constituting the charge generation layer:
An electrophotographic photoreceptor was produced in the same manner as in Test Example 1, except that a thin layer of μe-8IN:) was formed in place of the H thin layer.

μc-SiN:H thin layer is made by adding 5tH4 gas to 50%
SCCM.

1.2 SCCM of N2 gas, 500 S of N2 gas
It is introduced at a flow rate of CCM, and the pressure inside the existing container is l To
rr, and by applying 1.2 kW of high-frequency power.

In this case, the flow rate of N2 gas was increased for each μc-8IN:H thin layer formed to a final value of 5 SCCM, and the nitrogen concentration was changed from tO, 3M+% to 3 atoms.

When an image was formed using this photoreceptor in the same manner as in Test Example 1, a clear and high quality image was obtained.

Test, Test Example 3 An electrophotographic photoreceptor was manufactured in the same manner as Test Example 1, except that the charge generation layer was formed as follows.

After forming the charge retention layer, apply 5IH4 gas to 3QSCC.
M.

H2 gas 500 SCCM, CH4 gas 0.2
It is introduced at a flow rate of SCCM, and the pressure inside the reaction vessel is
Torr, 1. By applying OkWO high frequency power,
100X tic-8iC: H thin layer (carbon exposure degree 20.
3 atoms) were completely formed. Then CH4 has 0.8 S
A thin layer of 100 μc-8iC:H was similarly formed as a CCM. These operations were repeated to form a charge generation layer with a superlattice thickness of 3 μm. In addition, the latter μc
-8iC: During the formation of the H4 layer, the flow rate of CH4 increases with each thin layer formation, resulting in a final concentration of 58 CCM.
The carbon concentration was changed from 1 atom to 6 atoms.

Using this photoreceptor, an image was formed in the same manner as in Test Example 1, and a clear, high-quality image was obtained.

Test Example 4 During the formation of the former μ(!-3IC:H thin layer, the flow rate of CH4 increases with each thin layer formed, and finally 2
An electrophotographic photoreceptor was produced in the same manner as in Test Example 3, except that SCCM was used and the carbon hardness was changed from 0.3 atomic atoms to 3 atomic atoms.

When an image was formed using this photoreceptor in the same manner as in Test Example 1, a clear and high quality image was obtained.

Test Example 5 An electrophotographic photoreceptor f was produced in the same manner as Test Example 1, except that the charge generation layer was formed as follows.

That is, after forming the charge retention layer, SiH4 gas was applied at 50 SC.
CM.

H gas at 500 SCCM, N2 gas at 1. O.S.C.
CM is introduced in a continuous stream, and the pressure inside the reaction vessel is increased to l To
rr, and applying a high frequency generating force of 1 or 2 kW,
00X μC-3iN: H thin layer (nitrogen concentration 20.2
%) was formed. Then, a 100× μc-8IN:H thin layer was formed in the same manner using 3 SCCM of N2 gas. These operations were repeated to form a charge generation layer having a superlattice structure of 3 μm. In addition, the latter μc-SiN
:When forming the H thin layer, the KN2 gas flow rate ``f'' was increased for each thin layer, and finally 9 SCCM was obtained, and the nitrogen 4 degree was changed from 0.8 atomic atoms to 5 atomic atoms. .

When an image was formed using this photoreceptor in the same manner as in Test Example 1, a clear and high quality image was obtained.

Test Example 6 Except that the carbon concentration of the μc-8iC:H thin layer constituting the charge generation layer was changed as shown in FIGS. 3 to 5,
A 16-child photoreceptor was produced in the same manner as in Test Example 1.

When images were formed using these photoreceptors in the same manner as in Test Example 1, clear and high quality images were obtained.

The type of thin layer constituting the charge retention layer and the charge generation M is not limited to 2m type as in the above test example, but three or more types of thin layers may be laminated. It is sufficient to form different boundaries with a thickness of 1 m.

[Effects of the Invention] According to the present invention, since the photoconductive j8 uses a superlattice structure composed of laminated thin layers with mutually different optical band gaps, carrier mobility is high and high efficiency is achieved. An electrophotographic photoreceptor with excellent resistance and charging characteristics can be obtained. In particular, the present invention has the advantage that by appropriately combining the materials forming the thin layer, it is possible to obtain a photoreceptor having optimal optical waveguide characteristics for any wavelength band.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an electrophotographic photoreceptor according to an embodiment of the present invention, FIG. 2 is a diagram showing an apparatus for manufacturing an electrophotographic photoreceptor according to an embodiment of the present invention, and FIGS. 3 to 5 are FIG. 3 is a diagram showing changes in the concentration of carbon or nitrogen in a microcrystalline silicon thin film. 1: 4 conductive support, 2: barrier layer, 3: photoconductive layer, 4: surface layer, 5: charge retention layer, 6: charge generation layer. Figure 1 Figure 2 □ (c) (d) (e)
(f) Atsushi 3 Figures (a) (b) (c)
(d) (e) (f) Figure 4 (a) ki (c) (e) resistant (b) (d) (f) 5.

Claims (8)

[Claims] (1) In an electrophotographic photoreceptor having a conductive support and a photoconductive layer, the photoconductive layer is composed of a charge generation layer and a charge retention layer, and the charge retention layer includes a microcrystalline silicon thin film and a dark The charge generation layer is formed by alternately laminating two microcrystalline silicon thin films, at least one of which contains an element that increases dark resistance. An electrophotographic photoreceptor characterized in that the concentration of the element that increases the dark resistance in the microcrystalline silicon thin film varies from film to film in the layer thickness direction. (2) The electrophotographic photoreceptor according to claim 1, wherein the thin film has a thickness of 30 to 200 Å. (3) The electrophotographic photoreceptor according to claim 1 or 2, wherein the element that increases the dark resistance is at least one selected from hydrogen, carbon, oxygen, and nitrogen. (4) The photoconductive layer includes at least one element selected from elements belonging to Group III and Group V of the periodic table. The electrophotographic photoreceptor according to any one of the items. (5) A patent claim characterized in that a barrier layer made of an amorphous material or a semiconductor material in which at least a portion thereof is microcrystallized is formed between the conductive support and the photoconductive layer. The electrophotographic photoreceptor according to item 1. (6) The electrophotographic photoreceptor according to claim 5, wherein the barrier layer contains at least one element selected from elements belonging to Group III and Group V of the periodic table. . (7) The electrophotographic photoreceptor according to claim 5 or 6, wherein the barrier layer contains at least one element selected from carbon, oxygen, and nitrogen. (8) The electrophotographic photoreceptor according to claim 1, wherein a surface layer is formed on the photoconductive layer.