JPS62115463A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the photoconductive characteristics (electrophotographic characteristics) and environmental resistance of an electrophotographic sensitive body by using N-type a-Si as at least part of the sensitive body. CONSTITUTION:A charge transferring layer 23 and a charge generating layer 31 are formed on an electrically conductive support 21. The charge transferring layer 23 is made of a-Si contg. H and has 3-80mum thickness. At least one among C, O and N is incorporated into the layer 23 so as to increase the resistivity. The concn. of at least one among C, O and N in the layer 23 is changed so that it rises from the layer 31 side toward the support 21 side. The 1st layer 24 of the charge generating layer 31 is made of N-type a-Si and has 1-10mum thickness. The 2nd layer 25 is made of muC-Si contg. H and has 0.1-5mum thickness. The charge transferring layer 23 and the charge generating layer 31 contain at least one kind of element selected among the group III and V elements in the periodic table.

Description

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

[Prior art and its problems] Conventionally, inorganic materials such as CdS, ZnO, Se, 5e-Te, or amorphous silicon, or poly-N-vinylcarbazole (PVCZ) have been used as materials for forming the photoconductive layer of electrophotographic photoreceptors. ) or trinitrofluorene (T
Organic materials such as NF) are used. however,
These conventional photoconductive materials have various problems in terms of photoconductive properties or manufacturing, and these materials are used depending on the purpose of use, sacrificing the properties of the photoreceptor system to some extent.

For example, Se and CdS are materials that are harmful to the human body, and special consideration must be given to safety measures when manufacturing them. Therefore, there are problems in that the manufacturing equipment becomes complicated and the manufacturing cost is high, and in particular, Se needs to be recovered, which adds to the recovery cost. Also,
In the Se or S, 6-Te system, the crystallization temperature is 65
Since the temperature is as low as 0.degree. C., problems with photoconductive properties occur due to remaining snow during repeated copying, resulting in a short lifespan and low practicality.

Furthermore, ZnO is susceptible to oxidation-reduction and is significantly affected by the environmental atmosphere, resulting in a problem of low reliability in use.

Furthermore, organic photoconductive materials such as pvcz, T, and NF are suspected to be carcinogens and pose human health problems, and commercially available materials lack thermal stability and wear resistance. The drawbacks are low performance and short lifespan.

On the other hand, amorphous silicon (hereinafter abbreviated as a-812)
has recently attracted attention as a photoconductive conversion material, and is being actively applied to solar cells, bookmark transistors, and image sensors. As part of this application of a-3i, attempts have been made to use a-8i as a photoconductive material for electrophotographic photoreceptors, and photoreceptors using a-3i are recycled because they are non-polluting materials. No processing required;
Compared to other materials, it has advantages such as higher spectral sensitivity in the visible light region, high surface hardness, and excellent wear resistance and impact resistance.

This a-8i is based on the Carlson method (currently being studied as a photoreceptor, but in this case, the photoreceptor characteristics are required to have low resistance and low photosensitivity, however, both of these characteristics are required. Since it is difficult to satisfy the requirements with a single-layer photoreceptor, a layered structure is used in which 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. This satisfies these requirements.

By the way, a-3i is usually formed by a glow discharge decomposition method using silane gas, but at this time, a-3i is
Hydrogen is incorporated into the 3ill, and the electrical and optical characteristics vary greatly due to the difference in the amount of hydrogen. That is, as the amount of hydrogen entering the a-5i sample increases, the optical bandgap increases and the resistance of the a-5i increases, but as a result, the photosensitivity to long wavelength light decreases. For example, it is difficult to use it in a laser beam printer equipped with a semiconductor laser. Also, a-8il
If the hydrogen content in the film is high, depending on the film formation conditions, (
Those having a bonding structure such as SiHz)n and SiH2 may occupy most of the area in the film. Then,
Due to the increase in voids and silicon dangling bonds, the photoconductive properties deteriorate, making it unusable as an electrophotographic photoreceptor. Conversely, reducing the amount of hydrogen penetrating into a-8i reduces the optical band gap and its resistance, but increases photosensitivity to long wavelength light. However, when the hydrogen content is low, there is less hydrogen to combine with and reduce silicon dangling bonds. For this reason, the mobility of the generated carriers is reduced, the life span is shortened, and the photoconductive properties are deteriorated, making it difficult to use as an electrophotographic photoreceptor.

In addition, there is a technique to increase the sensitivity to long wavelength light by mixing C1 silane-based gas and germane GeH+ and performing glow discharge decomposition to produce a film with a narrow optical band gap, but in general, silane-based gas and GeH4
Since the optimum substrate temperature is different between the two methods, the produced film has many structural defects and cannot obtain good photoconductive properties.

Also, since GeH4 waste gas becomes toxic gas when oxidized, is there any way to treat the waste gas? ! It's rough. Therefore, such technology is not practical.

This invention was made in view of the above circumstances, and has excellent charging ability, low residual potential, high sensitivity over a wide wavelength range up to the near infrared region, and good adhesion to the substrate. An object of the present invention is to provide an electrophotographic photoreceptor having good environmental resistance.

[Means for Solving the Problems] The electrophotographic photoreceptor according to the present invention includes a conductive support, a charge generation layer, and a charge transport layer disposed between the charge generation layer and the conductive support. In the electrophotographic photoreceptor having a layer, the charge generation layer is formed of n-type amorphous silicon containing hydrogen and has a layer thickness of 1 to 1C1 m.
and is formed of amorphous silicon or microcrystalline silicon containing hydrogen and has a layer thickness of 0.1 to 5 μm.
The charge transport layer is formed of amorphous silicon containing hydrogen and having a layer thickness of 3 to 80 μm, and at least a part of the charge transport layer is made of amorphous silicon containing hydrogen and containing carbon, oxygen, and nitrogen. It is characterized in that it contains at least one selected element, and its concentration changes in the layer thickness direction.

The present invention was achieved by the inventors of the present invention, who have conducted various experimental studies in order to overcome the drawbacks of the prior art described above and to develop an electrophotographic photoreceptor that has both excellent photoconductive properties (electrophotographic properties) and environmental resistance. As a result, the present invention was completed based on the idea that this object could be achieved by using n-type a-8i for at least a portion of an electrophotographic photoreceptor.

This invention will be explained in detail below. The feature of this invention is that an n-type A-8i is used instead of the conventional A-8I. In other words, at least a part of the electrophotographic photoreceptor is formed of n-type a-8i, or is formed of a laminate of n-type a-3i and intrinsic semiconductor (i-type) a-3i, or is formed of n-type a-3i. A laminate of a-3i and microcrystalline silicon (hereinafter abbreviated as μc-8i), or n-type a-8
i and a-8i containing at least one element selected from C, O, and N. Also,
In the type of electrophotographic photoreceptor having a photoconductive layer,
N-type a-8i is used for the photoconductive layer.

The charge generation layer generates carriers upon irradiation with light. Part or all of the 111th layer of this charge generation layer is made of n-type a-3i containing hydrogen, and has a thickness of 1 to 10 μm. Moreover, the 21st I is formed of μC-8i or a-3i containing hydrogen H, and the layer thickness is as follows:
It is 0.1 to 5 μm. The charge transport layer is a layer that allows carriers generated in the charge generation layer to reach the support side with high efficiency, and therefore, the carriers must have a long life, high mobility, and high transportability. The charge transport layer is made of a-3i containing hydrogen. If the charge transport layer 811 is too thin or too thick, it will not fully exhibit its function. Therefore, the thickness of the charge transport layer is preferably 3 to 80 μm, more preferably 5 μm to 80 μm.
The thickness is from 50 μm to 50 μm.

Preferably, a barrier layer is provided between the conductive support and the charge transport layer. This barrier layer suppresses the flow of charge between the conductive support and the photoconductive layer, thereby enhancing the charge retention function on the surface of the photoreceptor and increasing the charging ability of the photoreceptor. In the Carlson method, when positively charging the surface of the photoreceptor, the barrier layer is made n-type in order to prevent electrons from being injected from the support side to the charge transport layer.

On the other hand, when the surface of the photoreceptor is negatively charged, the barrier layer is made n-type in order to prevent holes from being injected from the support side to the charge transport layer. It is also possible to form an insulating film on the support as a barrier layer. The barrier layer may be formed using μC-8i, or may be formed using a-8i.

N-type a-8i is formed by doping a-3i with an element belonging to Group Ⅰ of the periodic table, such as nitrogen N1 phosphorus P1 arsenic AS, antimony sb, and bismuth Bi. The n-type a-3i may be either an n-type lightly doped with these doping elements or an n+ type heavily doped, but it Considering the conductive properties, these doping elements should be added in an amount of 10 to 10
It is preferable to use n-type a-8i containing 3 atomic %.

μC-3i is a-
8i and polycrystalline silicon (polycrystalline silicon)
clearly distinguished from That is, in X-ray diffraction measurement, since a-3i is amorphous, only a halo appears;
Although no diffraction pattern can be observed, μc-3i shows a crystal diffraction pattern with 2θ around 27 to 28.56. In addition, while polycrystalline silicon has a dark resistance of 1060 cII, μc-8i has a dark resistance of 1Q1
It has a dark resistance of 1Ω·01 or more. This μC-51 is formed by agglomeration of microcrystals having a grain size of approximately several tens of angstroms or more.

As in this invention, an n-type a-
By using 3i, long wavelength light, especially 790
It is possible to obtain an electrophotographic photoreceptor that is highly sensitive even to semiconductor laser light having an oscillation wavelength in the vicinity of nm. Therefore,
The electrophotographic photoreceptor according to the present invention can be applied not only to an RPC (plain paper copying machine) but also to a laser printer equipped with a semiconductor laser. In Figure 1, the horizontal axis is PH
The doping ratio of P shown in s/5i2Hs gas flow ratio is taken, and the vertical axis is the conductivity of n-type a-3i (1/Ω・Cta).
FIG. 2 is a graph showing the influence of doping ratio on conductivity. Flow rate ratio P of PH3 gas in this film forming gas
As H3/5ins increases, the content of P element in n-type a-8i increases, making it strong n-type (n+). As shown in Figure 1, when P is not included, the conductivity σ0 in the dark is 3.87X10-11 <1/Ω・Representative), and the conductivity σ0 when irradiated with a 790 nm laser beam. ,
(7900m) is 1.15X10-' (1/Ω・0
). However, increasing the doping ratio increases the conductivity and the PH3/S 1285 doping ratio is 33
In the case of Dpm, (7p (790nl) is 5.57
x10-' (1/Ω·υ), which is an increase of more than one order of magnitude compared to the case where P is not doped. In addition, in this case, σD is also 5,28X10-' (1/Ω・Ct
S), and as the doping ratio increases, ap
(790nl) and σD both increase, but in the end,
When the doping ratio is in the range of 1 o -s to 10 -6 , ap (790 nl) becomes an order of magnitude higher than that without P doping, and the S/N ratio can be increased to about three orders of magnitude. Therefore, an n-type a-3i in which the first layer of the charge generation layer is doped with P or the like at this level of doping ratio.
By using this, a photoreceptor having sufficiently high sensitivity to long wavelength light can be obtained, and can be put into practical use as a photoreceptor for laser printers.

Next, by making a-3i n-type in this way,
The reason why sensitivity to long wavelength light can be increased will be explained. FIG. 2 is a graph showing the relationship between the PH3/S i Hs doping ratio on the horizontal axis and the optical band gap and activation energy on the vertical axis. As is clear from FIG. 2, the optical bandgap does not change even when the doping ratio is changed, and remains substantially constant. On the other hand, the activation energy ΔE becomes smaller as the doping ratio is increased. In this case, the optical bandgap Ea is li! [It is the energy difference between the ilf child band and the conduction band, and the activation energy ΔE is the energy difference between the Fermi levels F, L and the conduction band.

The optical band gap Ea is the energy required to excite electrons from the valence band to the conduction band, and the smaller the optical band gap Ea, the lower energy light can be absorbed to generate carriers. On the other hand, the Fermi level FL exists between the conduction band and the valence band, and the smaller the activation energy, the more easily carriers are excited. Therefore, the smaller the activation energy, the higher the sensitivity to long wavelength light with a smaller hv (blank constant X frequency), and the more carriers are excited. By using n-type a-8i in the charge generation layer as in this invention, the sensitivity to long wavelength light increases as shown in Figure 1. By doping a-5: to make it n-type, the Fermi level F-L increases, and as a result, the activation energy ΔE decreases, and the sensitivity to low-energy light (long wavelength light) increases. This is thought to be because of this.

On the other hand, when n-type a-8i is used for the charge generation layer, the dark specific resistance of the charge generation layer becomes low and the charge retention ability becomes low. In order to compensate for this, μc-8i or a-3i containing hydrogen is used for the 211st layer of the charge generation layer, and the charge generation layer is formed of this second layer and n-type a-8i. It has a laminate structure with the first layer. This allows the n-type a-8i first
! The low dark specific resistance of i1 is compensated for by the 211th (high resistance), and a highly practical photoreceptor can be obtained.

Note that the optical energy gap Ea of μc-5i is a
−3i optical energy gap Ea (1,65 to 1
．． 708V).

Therefore, μc-8i can absorb even near-infrared light, which has a longer wavelength and lower energy than visible light, and has high photosensitivity on the long wavelength side. Also, μc-5i is a-
Carrier mobility is higher than that of 8i.

Such a charge generation layer having n-type a-3i is formed by using silane gas as a raw material and phosphine gas (PH3 gas) as a dopant gas using a high frequency glow discharge decomposition method to form a conductive support. It can be manufactured by depositing n-type a-8i on top. In this case, the hydrogen content in the layer can be controlled by diluting high-order silane gas such as SiH4 and 3i2H6, which are raw material gases, with hydrogen or by mixing hydrogen gas with a silane gas. Furthermore, by using a diluent gas, it is possible to increase the deposition rate and form uniform plasma.

FIG. 3 is a diagram showing an apparatus for manufacturing an electrophotographic photoreceptor according to the present invention. Gas cylinders 1 and 2°3.4 are each filled with, for example, SiH4,812Ha.

Raw material gases such as 82 Hs, H2, CH4, etc. are accommodated. The gas in these gas cylinders 1.2.3.4 is
Flow! It is supplied to a mixer 8 via an adjustment valve 6 and piping 7. A pressure gauge 5 is installed in each cylinder, and while monitoring this pressure gauge 5, a valve 6
By adjusting 11 and the mixing ratio of each raw material gas supplied to the mixer 8, it is possible to adjust the mixing ratio. The gases mixed in the mixer 8 are supplied to a reaction vessel 9. A rotating shaft 10 is attached to the bottom 11 of the reaction vessel 9 so as to be rotatable around the vertical direction, and a rotating shaft 10 is attached to the upper end of the rotating shaft 10.
A disk-shaped support base 12 is fixed with its surface perpendicular to the rotating shaft 10. Inside the reaction vessel 9, there is a cylindrical electrode 13.
aligns its axial center with the axial center of the rotating shaft 1o and rotates the bottom 1.
It is installed on 1. A drum base 14 of a photoreceptor is placed on a support base 12 with its axial center aligned with the axial center of the rotating shaft 10, and a heater 15 for heating the drum base is arranged inside the drum base 14. It is set up. Electrode 1
3 and the drum base 14, a high frequency '21fil1
16 is connected so that a high frequency current is supplied between the electrode 13 and the drum base 14. Rotating axis 1
0 is rotationally driven by a motor 18. The pressure inside the reaction vessel 9 is monitored by a pressure gauge 17, and the reaction vessel 9 is connected via a gate valve 18 to an appropriate evacuation means such as a vacuum pump.

When manufacturing a photoreceptor using an apparatus configured as described above, after installing the drum base 14 in the reaction vessel 9, the gate valve 19 is opened to increase the inside of the reaction vessel 9 to approximately 0.1 Torr. evacuate to below the pressure of r). Next, the required reaction residues from the cylinders 1.2 and 3.4 are mixed at a predetermined mixing ratio and introduced into the reaction vessel 9. In this case, the flow rate of the gas introduced into the reaction vessel 9 is set so that the pressure within the reaction vessel 9 is 0.1 to 1 Torr. Next, the motor 18 is operated to rotate the drum base 14, the heater 15 heats the drum base 14 to a constant temperature, and the high frequency tube [16] supplies a high frequency current between the electrode 13 and the drum base 14. , forming a glow discharge between the two. As a result, a-3i is deposited on the drum base 14. Note that N20. NH3, NO2, N
2.

By using CH4, C2H4,02 gas, etc.
These elements can be contained in a-3i.

As described above, the electrophotographic photoreceptor according to the present invention can be manufactured in a closed system with 1llfI packaging, similar to that using the conventional a-3i, and is therefore safe for the human body. Furthermore, this electrophotographic photoreceptor has excellent heat resistance, moisture resistance, and abrasion resistance, so it has the advantage of having a long lifespan with little deterioration even after repeated use over a long period of time. Furthermore, since a long wavelength sensitizing gas such as QeH4 is not required, there is no need to provide waste gas treatment equipment, and industrial productivity is extremely high.

It is preferable that n-type a-8r1a-3+ or uc-8i contain hydrogen in an amount of 0.1 to 30 atomic percent. As a result, dark resistance and light resistance become harmonious,
Photoconductive properties are improved. Doping hydrogen into the n-type a-8i, a-8i or μc-8i layer is performed using, for example, a glow discharge decomposition method using a silane-based raw material gas such as SiH+ and 5i2Ha, and a carrier gas such as hydrogen. may be introduced into the reaction vessel to cause glow discharge, or a mixed gas of silicon halides such as S i F4 and 5iCI4 and hydrogen gas may be used, or a mixture of silane gas and silicon halide may be used. The reaction may be performed with a mixed gas of Furthermore, the n-type a-8i layer and the like can be formed not only by the glow discharge decomposition method but also by a physical method such as sputtering.

It is preferable to dope with at least one element selected from n-type a-3i, a-8i, or μc-si mini;t, nitrogen N, carbon C, and Ill element O.

This makes it possible to increase the dark resistance of n-type a-8i, etc., and improve the photoconductive properties.

In order to make μc-3i and a-8i p-type, it is preferable to dope them with elements belonging to Group Ⅰ of the periodic table, such as boron B1 aluminum AI, gallium Qa, indium In, and thallium T1. , μc-5i
In order to make a-8i and a-8i n-type, it is preferable to dope it with an element belonging to Group V of the periodic table, such as nitrogen N1 phosphorus P1 arsenic As, antimony sb, and bismuth 3i. By doping with this n-type impurity or n-type impurity, a barrier layer that prevents charge injection from the support into the charge transport layer can be formed.

μc-3i and a-8i themselves are somewhat n-type, but
By lightly doping (10-7 to 10''3 atomic %) an element belonging to Group Ⅰ of the periodic table into the charge generation layer, charge transport layer or barrier layer formed of μC-8i or A-8i, The charge generation layer, charge transport layer, or barrier layer becomes an i-type (intrinsic) semiconductor, has a high dark resistance, and improves the S/N ratio and charging ability.

In this invention, the second N of the charge generation layer is formed of a-8i or μC-3i. μC-8i has a small optical bandgap and high sensitivity to long wavelength light, so by forming the second layer with μC-8i in this way, it can absorb light from visible light to long wavelength light with even higher efficiency. I can do it.

Moreover, since μc-3i has few structural defects, carrier mobility is high and running properties are good. Therefore, carriers move with high efficiency in this charge transport layer.

The charge transport layer is formed of a-3i containing hydrogen, and C
, O, and N. These C, O, and N are distributed so that their concentrations vary in the layer thickness direction in all or part of the charge transport layer. In this case, it is preferable that the concentration of C, 0, N increases from the charge generation layer toward the conductive support. In this way, by changing the concentration of the doping element in the layer thickness direction, separation of the layers at the boundaries between the layers can be prevented. Also, a-3i has C,
By containing O and N, the band gap of a-3i is expanded, and the movement of carriers from the conductive support to the N charge generation layer is suppressed.

Since it is preferable that the wA region where movement is suppressed be near the conductive support, the concentration distribution is preferably such that the concentrations of C, O, and N are higher on the side of the conductive support.

Preferably, a surface layer is provided on the charge generation layer. Since the a-8i or μc-8i charge generation layer has a relatively large refractive index of 3 to 4, light reflection easily occurs on the surface. When such light reflection occurs, the ratio of the amount of light absorbed by the charge generation layer decreases, and light loss increases. For this reason, it is preferable to provide a surface layer to prevent reflection. Further, by providing the surface layer, the charge generation layer is protected from loss. Furthermore, by forming the surface layer, the charging ability is improved, and the charge can be easily deposited on the surface. Materials forming the surface layer include Si 3 N+, Si
○2, SiC, A1203, a-8iN:HSa
There are inorganic compounds such as -8iO:H, and a-8iC:H, and organic materials such as polyvinyl chloride and polyamide.

Embodiment FIGS. 4 to 6 are partial sectional views showing an electrophotographic photoreceptor according to an embodiment of the present invention. In the photoreceptor shown in FIG. 4, a charge transport layer 23 is formed on a conductive support 21, and a charge generation layer 11 is formed on the charge transport layer 23.
31 is formed.

The charge generation layer 31 is composed of a laminate including a first layer 24 formed on the conductive support 21 side and a second layer 25 formed on the surface side. In the photoreceptor shown in FIG. 5, the charge generation layer 32 formed on the charge transport layer 23 has a second layer 25 formed on the conductive support side and a layer 11124 formed on the surface side. . Furthermore, in the photoreceptor shown in FIG. 6, a barrier layer 22 is formed between the conductive support 21 and the charge transport layer 23, so that charges can be generated! A surface layer 26 is formed on I31.

The charge transport layer 23 is made of a-8i containing H, and has a layer thickness of 3 to 80 μm.

This charge transport 123 has a high resistance by containing C, O, and N. It is preferable that the concentrations of C, O, and N are changed in the layer thickness direction so that their concentrations increase from the charge generation layer 31, 32 toward the conductive support 21.

The first layer 24 of the charge generation layer 31, 32 is an n-type a-8i
The layer thickness is 1 to 10 μm. The second layer 25 is μc-3i or a-3i containing H.
It is formed of. It is preferable that this second layer 25 is lightly doped with an element belonging to group m of the periodic table to make the second layer 1 type to increase dark resistance and improve photoconductive properties.

The thickness of this 211250th layer is 0.1 to 5 μm.

Next, embodiments of the invention will be described.

The inside of the reaction vessel 111 is evacuated by a diffusion pump (not shown),
Create a vacuum of approximately 0.1 torr. Thereafter, the drum base is heated and maintained at about 400°C. Then 200SCCM
SiH+ gas with a flow rate of , 82 H6 gas with a flow rate ratio of 10-3 to this Si H4 gas flow rate, and 1100
5 CC of CH4 gas was mixed and supplied to the reaction vessel. Thereafter, the inside of the reaction vessel was evacuated using a mechanical booster pump and a 0-tally pump, and the pressure was adjusted to 1 Torr.

A high frequency power of 300 watts at 13.56 M)-12 was applied to the electrode to generate a plasma between the electrode and the drum substrate, which was allowed to grow for 15 minutes to form a 1.8 μm A-8i barrier layer. .

Then 5008 CCM of 5il-14 gas and 110
08CC of CH4 gas was introduced into the reaction vessel and film was formed for 2 hours under the conditions of reaction pressure of 0.8 Torr and high frequency power of 1kW, and then CH4 gas was changed from 11005CC to 50SC.
CM was reduced for 1 minute, and a film was formed under these conditions for 1 hour.

Further, the CH4H4 gas flow rate was lowered to 108 CC, and film formation was performed under these conditions for 2 hours. As a result, a-3: a charge transport layer having a thickness of 28 μm was formed.

Then 50SCCM of 5i2Hs gas and 5i2Hs
A PHs gas with a flow rate ratio of 10-5 to the gas was introduced into the reaction vessel, the reaction pressure was 0.4 Torr, and the high frequency power was 10
The film was formed for 1 hour under the condition of 0 watts, and the n-type a-, 3i first
A layer of 8 μm was formed. Then S i of 300SCCM
Ratio of H4 gas to SiH4 gas is 3X10
82 H6 gas was introduced into the reaction vessel, and the reaction pressure was 0.8 torr and the high frequency power was 200 watts.
The a-8i second layer was formed to a thickness of 3 μm by sensitization for 20 minutes. After that, 300SCCM of SiH+ gas and 1% of CH4 gas were added.
50SCCM, reaction pressure 1 Torr, high frequency power 200
A surface layer of 1 .mu.m was formed by setting the temperature at 100.degree. C. for 15 minutes.

The photoreceptor thus formed was attached to a laser printer equipped with a semiconductor laser having a wavelength of 790 nm, and its electrostatic properties were measured. As a result, the half-decrease exposure amount was 9.5 e.
ra cm2 and 35er! The residual potential at an exposure dose of 11C+02 is 20V, and it has extremely excellent sensitivity.

! This example differs from Example 1 in that the second layer of the charge generation layer was formed of μc-8i. In other words,
The second layer of the charge generation layer is made of μc-8i by adding 6008 CCM of H2 gas in addition to SiH+ gas and 8286 gas.
ll was formed. The layer thickness of this μc-8i second layer is also 3 μm.
Met.

The photoreceptor film formed in this way has a wavelength of 790 ni
As a result of attaching it to a laser printer equipped with a semiconductor laser and measuring its electrostatic characteristics, the half-decrease exposure amount was 9 Oe.
rg C12, the residual potential at 35 era cm2 is 35 V, and it is extremely sensitive.

[Effects of the Invention] - According to the present invention, the electronic material has high resistance, excellent charging characteristics, high photosensitivity in the visible light and near-infrared light regions, is easy to manufacture, and has high practicality. A photographic photoreceptor can be obtained.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between doping ratio and electrical conductivity, FIG. 2 is a graph showing the relationship between doping ratio, activation energy, and optical band gap, and FIG. 3 is an electrophotograph according to the present invention. FIGS. 4 to 6 are cross-sectional views showing an electrophotographic photoreceptor according to an embodiment of the present invention. 1.2.3.4: Cylinder, 5; Pressure gauge, 6; Valve, 7
; Piping, 8: Mixer, 9; Reaction container, 10; Rotating shaft, 1
3: Electrode, 14 Nidrum substrate, 15; Heater, 16; High frequency power supply, 19; Gate pulp, 21; Support, 22;
Barrier layer, 23: N transport layer, 24; first layer, 25; second
Layer, 26; Surface layer, 31.32: Charge generation layer. Applicant's agent Patent attorney Takehiko Suzue PHa/5izHs Figure 1 1j Figure 3

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor comprising a conductive support, a charge generation layer, and a charge transport layer disposed between the charge generation layer and the conductive support, the charge generation layer comprises: A first layer made of n-type amorphous silicon containing hydrogen and having a layer thickness of 1 to 10 μm; and a second layer made of hydrogen-containing amorphous silicon or microcrystalline silicon and having a layer thickness of 0.1 to 5 μm. The charge transport layer contains hydrogen and has a layer thickness of 3 to 80 μm.
It is characterized by being formed of amorphous silicon of m and containing at least one element selected from carbon, oxygen and nitrogen in at least a part of the region, the concentration of which changes in the layer thickness direction. Electrophotographic photoreceptor. (2) The charge transport layer and the charge generation layer are
The electrophotographic photoreceptor according to claim 1, which contains at least one element selected from elements belonging to Group III or Group V.