JPH01295266A - Photoconductive member - Google Patents

Abstract

PURPOSE:To obtain excellent electrification characteristics and to form a sharp good-quality image even with a laser beam printer and the like by forming a bulk layer or a well layer composed of a-Si:H type thin layers having superlattice structure continuously changed in the H content in each layer. CONSTITUTION:The electric charge generating layer 50 of a part of a photoconductive layer is made of a-Si:H of superlattice structure formed by alternately laminating barrier layers 50a and the well layers 50b different in the band gap in each layer, accordingly, the layers 50 generate many carriers by irradiation with light as compared with the charge generating layer formed in a single layer, it has high spectral sensitivity, and yet it has high carrier mobility, extended life, and superior photoconductive characteristics. The barrier layers 50a maintain the optical band gap above a constant value and do not invite lowering of resistance, thus permitting high spectral sensitivity to be obtained in a wide wavelength region from the visible wavelength region to the near infrared wavelength region, and applied to the laser beam printer, and a sharp and good-quality image to be obtained.

Description

[Detailed description of the invention]

[Object of the Invention] (Industrial Application Field) The present invention relates to a photoconductive member that forms an electrostatic latent image in an image forming apparatus such as a copying machine or a laser beam printer. (Prior Art) In recent years, with the diversification of functions and models of image forming apparatuses such as electrophotographic apparatuses, photoreceptor materials such as cadmium sulfide [CdS], zinc oxide [ZnO], and selenium (Se) have been used.
, selenium telluride alloy [5e-Te1, etc.], poly-N-vinylcarbazole (hereinafter referred to as PVCz).
Various types of organic material tubes have been developed, such as , trini-1 herofluorene (hereinafter referred to as TNF), and the like. However, among the photoreceptor materials, selenium [SO3,
Since cadmium sulfide [CdS] is a material that is inherently harmful to the human body, safety measures must be taken during manufacturing, which complicates the manufacturing equipment and increases manufacturing costs. This has to be recovered, which not only increases the cost by 1% but also has the low crystallization temperature of about 65°C for selenium [Se3, selenium-tellurium alloy 1:5e-Te3]. Because of this, it tends to crystallize, and during repeated copying, a residual charge is generated in the crystallized portion, which tends to cause problems such as staining the image, and ultimately, it has the disadvantage that it cannot achieve a long service life. Due to its physical properties, zinc oxide [ZnO] is susceptible to oxidation-reduction, is significantly affected by environmental conditions such as temperature and humidity, and has the drawback of unstable image quality and poor reliability. In addition, organic materials such as (PVCz) and (TNF) have poor thermal stability and wear resistance, making it difficult to extend their service life.2) Recently, they have been suspected of being carcinogenic. . Therefore, as a solution to the drawbacks mentioned in recent years, it is non-polluting and does not require recovery treatment, has a high surface hardness, has excellent wear resistance and N impact resistance, and is even higher than conventional methods. Amorphous silicon with spectral sensitivity (hereinafter referred to as a-3j
, :H. ) is being considered for application to photoreceptor materials. Specifically, since the photoreceptor is required to have high resistance and high spectral sensitivity, in order to satisfy both of these characteristics, a conductive support and (a-3i:I-()
A laminated type (a-3i:
H) A photoreceptor has been developed. However, when forming a film by a glow discharge decomposition method using a gas containing silane [S],
(a-5j Go1) Hydrogen atoms [H'] incorporated into the film
The problem is that the electrical characteristics and optical characteristics vary greatly depending on the amount of . That is, (a-3j,
: As the amount of hydrogen atoms [H] incorporated into the T() film increases, the optical bandgap becomes larger and the resistance becomes higher. When used in a laser beam printer using a semiconductor laser, fogging, crushed type, afterimages, uneven density due to interference fringes, etc. may occur, making the printer unusable. Sj
Bond structures such as l+2) n) bonds and [5xH2] bonds become dominant in the (a −3j,: H) film, and as a result, (S j l+ '1 bonds are broken and dangling Structural defects such as bonds and voids increase,
There is a problem that photoconductivity deteriorates. On the other hand (a-5
j:I() When the amount of hydrogen atoms [H] incorporated into the film decreases, the spectral sensitivity to long wavelength light increases, but on the other hand,
The optical bandgap becomes smaller and the resistance becomes lower, and hydrogen atoms [H] no longer compensate for the dunking bonds, so the mobility and lifetime of the generated carriers decreases to -3~, which also reduces photoconductivity. There is a problem that the photoreceptor becomes inferior in quality and cannot be used as a photoreceptor. (Problem to be Solved by the Invention) Conventionally, the spectral sensitivity characteristics or resistance values of (a-3i:I()) conflict with each other in response to changes in the hydrogen content in the (a-3j,:H) film. It has excellent optical and electrical properties (a-5i: H
) A problem arises in that it is not possible to obtain a photoreceptor, leading to deterioration in image quality. Therefore, the present invention solves the above problems by using a non-polluting material with high surface hardness (a-3i:H), which maintains high resistance, provides excellent electrical resistance characteristics, and has high resistance over a wide wavelength range. The purpose is to provide a photoconductive member that has spectral sensitivity characteristics, can obtain clear and high-quality images even with laser beam printers, has good adhesion to substrates, and has excellent environmental resistance. shall be. [Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides at least a portion of the photoconductive layer with 30 [people] to 200 [people] (a-3
A large number of bulk layers and well layers consisting of thin layers of the i:I() system are laminated, and the hydrogen content in either the bulk layer or the well layer, or both layers, is continuously varied for each layer. It has a superlattice structure. (Function) The present invention can be applied to laser beam printers, etc. by improving photoconductive properties over a wide wavelength range and preventing deterioration of spectral sensitivity characteristics and charging characteristics for long wavelength light by the above means. This makes it possible to (Example) In explaining the present invention in detail, first, the principle of the present invention will be described. That is, it may be either crystalline or amorphous, but it is extremely thin, with a thickness of about 30 to 200 people, and is a stack of multiple thin layers with different optical pans and gaps. Regardless of the absolute size of the optical bandgap itself, the layer with the relatively smaller optical bandgap knob is used as the well layer, and the optical huff 1~gap is A superlattice structure having a periodic potential barrier is formed, with the relatively larger layer serving as a barrier layer. In this superlattice structure,
Since the barrier layer is extremely thin, one of the carriers in the thin layer
~Due to the tunnel effect, carriers easily pass through the barrier layer, are accelerated by the electric field in the superlattice structure, and travel through the superlattice structure with higher mobility than in the case of a single layer. Furthermore, in this superlattice structure, a significantly larger number of carriers are generated compared to the number of carriers generated in a single layer upon incidence of light, resulting in high spectral sensitivity. Furthermore, in the potential well layer, the superlattice structure has excellent photoconductive properties, as the lifetime of carriers is 5 to 10 times longer than in the case of a single layer due to quantum effects. Specifically, the photoconductive member is formed as shown in FIGS. 4 to 9, and is shown in FIG. 4 (Specific Example 1).
In this method, a charge injection prevention layer (layer [1]) is formed on the top of the conductive support (10), and a photoconductive layer (12) and a surface layer (13) are formed on the charge injection prevention layer (11). ) is formed. In addition, (specific example 2) shown in Figure 5 is (specific example)
-), the photoconductive layer (12) is functionally separated into a charge generation layer and a charge transport layer, and the conductive support (10
) and the charge transport layer (16) on the charge injection prevention layer (11).
) is formed. A charge generation layer (17) is formed on the second side of the charge transport layer (16), and a surface layer (13) is formed on the charge generation layer (17). In (Specific Example 1), the photoconductive layer (2) generates carriers upon incidence of light, and one polarity of these carriers neutralizes the charges on the photoreceptor surface, and the other polarity neutralizes the charges on the surface of the photoreceptor. runs through the photoconductive layer (12) to the electrically conductive support (1o). Further, in (Specific Example 2), carriers are generated in the charge generation layer (17) by the incidence of light, and one of these carriers travels through the charge transport layer (16) and transfers to the conductive support ( 1
0). When the photoconductive layer (12) or the charge generation layer (17) in these (specific examples) is enlarged, it becomes as shown in FIG.
It has a superlattice structure in which the first (a-3i near-H)ffi (18) and the second (a-3i: H) layer (20) of [person] to 200 [person] are laminated alternately. There is. The first (a-5i:I() layer (18) has a hydrogen content of 30 [%], and the second (a-5i nide ■) layer (20
) has a hydrogen content of 12%, and when the hydrogen content is continuously varied in the photoconductive layer (12) or the charge generation layer (17) as shown in FIG. - The maximum optical bandgap of the (a-3i:H) layer (18) is ], , 8[eV], and the second (a-3j,
: H) Minimum optical bandgap of layer (20)],
, 68 [eV], the energy band diagram in the thickness direction in the superlattice structure is the first (
The a-3i:I() layer (18) serves as a potential barrier, while the second (a-3i:H) layer (20) serves as a potential well, and a potential barrier layer and a well layer are formed periodically. It will be done. In addition, each layer (18), (20
) by changing the optical bandgap or layer thickness,
The bandgap of the layer having a Peter junction superlattice structure can be freely adjusted. In addition, as for the material forming such a superlattice structure, the hydrogen content is 30 [atomic %] and the gap is 1.
(a-3i:)I) with hydrogen content of 12 [atomic %] and bread gap of 1.68 [:eV), etc.
Alternatively, to adjust the optical bandgap, nitrogen [
Amorphous silicon nitride containing N], carbon [C], and oxygen [○] (hereinafter referred to as a-3iN:H),
Amorphous silicon carbide (hereinafter referred to as a-3iC: I-
It is called I. ), amorphous silicon oxide (hereinafter a-5
”O:H. ) etc. (a-3i:I() system), these generally exhibit weak n-type when undoped, and increase the doping of elements in group Ⅰ of the periodic table such as boron CB) and aluminum [A11]. However, by increasing the doping of elements in group Ⅰ of the periodic table, such as phosphorus [P] and nitrogen [N'1], n-type characteristics become noticeable. becomes. Furthermore, carrier mobility is further improved by doping with an element of Group 1I or V of the periodic table. Other materials include amorphous germanium silicon (hereinafter referred to as a-3iGe: H) having an optical band gap of 1.5 [eV].
Amorphous germanium nitride (hereinafter a-GeN:H
It is called. ), amorphous germanium carbide (hereinafter a-
There are also GeC:I (hereinafter referred to as a-GeO:H), amorphous germanium oxide (hereinafter referred to as a-GeO:H), and the like. In addition to the fluctuation of the optical bandgap, in each of these materials, it is necessary to compensate for the dangling bonds of silicon, balance dark resistance and bright resistance, and improve photoconductivity. In order to achieve this, hydrogen (H) must be between 0.01 and 30
It is desirable that it contains [atomic %] gold. And for example (a
-3i:H) by the glow discharge decomposition method, silane gases such as silane [:5j-11,1 and disilane (SX2+++;]) are introduced into the reaction chamber as raw materials, and high-frequency H can be added into the thin layer by glow discharge.On the other hand, (a-3jN:)
In order to form I), nitrogen gas [N2] is added to the raw material gas.
Alternatively, a required amount of ammonia gas (Ni+3) or the like may be added. Furthermore, (a-3jGe:)() is usually silane (
The film is formed by glow discharging a mixed gas of Sj, Hj and germane (Ge1(4)).If necessary, hydrogen gas [N7] or helium gas (t+el is used as a carrier gas for silanes). On the other hand, silicon halides such as silicon tetrafluoride [Sj F4] gas and 1-lichlorosilane [:5iCf+,...] gas can also be used as raw material gases. Even when reacted with a mixed gas with silicon halide gas, H-containing (a-5iN:I() and (
a-3i:H) can be formed into a film. Note that these thin layers can be formed not by the glow discharge decomposition method but also by a physical method such as sputtering. Note that the charge injection prevention layer (11) in (Specific Example 1) and (Specific Example 2) consists of a conductive support (10) and a photoconductive layer (
]2) Alternatively, by suppressing the flow of charge between the photoreceptor and the charge generation layer (17), the charge retention function on the surface of the photoreceptor is enhanced, and the charging ability of the photoreceptor is enhanced. In the Carlson method, when the surface of the photoreceptor is positively charged, the charge injection prevention layer is made of an n-type semiconductor in order to prevent electrons from being injected from the support side to the photoconductive layer. On the other hand, when the surface of the photoreceptor is to be negatively charged, the chargeable anti-static layer is made of an n-type semiconductor in order to prevent holes from being injected from the support side to the photoconductive layer. It is also possible to form an insulating film on the support as a charge injection prevention layer. As the semiconductor charge injection prevention layer, microcrystalline silicon (hereinafter referred to as μC-S ConiH) or (a-3i:H) may be used. And (μC-3i:H) and (a-3i:H) are p
In order to make a mold, elements belonging to Group Ⅰ of the periodic table, such as boron [B], aluminum [AQ:l, gallium I:Ga], indium [In:], and thallium (T
I2) etc. is preferably doped, (μC-3
]: In order to make I() and (a-3i:H) n-type, an element belonging to Group V of the periodic table, such as nitrogen [N],
It is preferable to dope with phosphorus [■]], arsenic [As], antimony (sb), bismuth (Bi), or the like. By doping with this n-type impurity or n-type impurity,
Charge migration from the support side to the photoconductive layer is prevented. On the other hand, (μC-5i:H) and (a-3i:I()
, carbon [C'l, nitrogen (N) and oxygen]

By containing at least one element selected from [0],
A high resistance insulating charge injection prevention layer can be formed. The thickness of the charge injection prevention layer is between 100 and 10 mm.
[Proof] is preferred. Furthermore, in (Specific Example 1) and (Specific Example 2), a surface layer (13) is provided on the photoconductive layer M (12) or the charge generation layer (1, 7) l for the following reason. That is, (a −3i:
H) etc. have a relatively large refractive index of 3 to 3.4, so 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 surface layer (13) to prevent reflection. Further, by providing the surface layer (13), the photosensitive layer (12) or the charge generation layer (17) is protected from damage. 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 (a-5iN:I(), (
a-3j, O: H), and (a-3iC: H)
and organic materials such as polyvinyl chloride and holamide. When the surface of the photoconductive member constructed in this way is charged with a positive voltage of about 500 [V] by corona discharge, for example, in the functionally separated type shown in FIG. 5 (Example 2), A potential barrier as shown in FIG. 9 is formed. When light (HV) is incident on this photoconductive member, the superlattice structure of the charge generation layer (17) causes electrons (21) and holes (2
2) carriers are generated. Electrons (21) in the conduction band are accelerated toward the surface layer (13) by the electric field in the photoconductive member, and holes (22)
is accelerated toward the conductive support (10) side. In this case, the number of carriers generated at the boundary between thin layers with different optical band gaps is much larger than the number of carriers generated in the bulk. Therefore, the charge generation layer (17) having this superlattice structure has high spectral sensitivity. Also,
In the potential well layer, due to quantum effects,
The carrier lifetime 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 equal to the bulk mobility. The carrier has excellent runnability. As described above, a photoconductive member having a superlattice structure in which thin layers with different optical bandgaps are laminated can obtain high photoconductive properties and produce clearer images than conventional photoreceptors. can. Based on the above principle, one embodiment of the present invention will be described below with reference to FIGS. 1 to 3. Glow discharge device (
26) Inside the reaction vessel (27) is an electrosensitive support,
In order to support a drum-shaped base (28) made of aluminum, a support (32) has a built-in heater (30) and is rotated by a motor (31) via a shirt h (31a).
A support stand (33) is provided to support the support rod (32). Also, the circumference of the support rod (32) is 1.3,
It is connected to a high frequency power source (34) of 56 (MHz:l) and is surrounded by a cylindrical electrode (36) supported on the bottom (27a), and the support rod (32) J1 is filled with silane gas [5jH4]. , diborane gas [5i2H, ],
A large number of gas cylinders (37
A gas introduction pipe (40) is provided which is connected to a gas supply system (38) having a) (37n) and a gas mixer (38a) via a gas introduction valve (40a). In addition, (41a) - (41n) are each gas cylinder (37a).
The valve (37n) and (42a) and (42n) are pressure gauges. Furthermore, (43) is an exhaust valve connected to an exhaust device (not shown) that exhausts the inside of the reaction container (27), and (44) is a vacuum gauge that measures the atmospheric pressure inside the reaction container (27). . In addition, (46) is a photoreceptor such as a laser printer, which is a photoconductive member, and a drum-shaped base (28) has a charge injection prevention layer (47) and a charge transport layer (48), and a band with a high hydrogen content. Barrier layer with large gap (50a
) and a charge generation layer (50) and a surface layer (51) each having a heterojunction superlattice structure in which well layers (50b) with low hydrogen content and a small band gap are alternately laminated to an arbitrary thickness. . However, the charge generation layer (50
), the barrier layer (50a) and/or the well layer (50a)
The hydrogen content of 0b) is continuously varied from layer to layer. Note that (52) is a charge transport layer (48) and a charge generation layer (5).
0). When forming the photoreceptor (46) in the glow discharge device (26), after placing the drum-shaped substrate (28) on the support rod (32), the interior of the reaction vessel (27) is The exhaust valve (43) is opened so that the atmospheric pressure is below 1.5 mm, and the exhaust gas is treated by the exhaust device (not shown), and the drum-shaped substrate (28) is heated to a predetermined temperature by the heater (30). Then, a required predetermined gas is supplied from the gas supply system (38) to the reaction vessel (
27), and the gas pressure in the reaction vessel (27) was set to 0.1.
Applying the necessary power between the drum-shaped substrate (28) and the cylindrical electrode (36) for a predetermined period of time using a high-frequency power source (34) while maintaining it constant within a range of about 1 to 1 Torr;
A charge injection prevention layer (47) is formed on the drum-shaped substrate (28)l. Subsequently, the charge transport layer (48), A charge generation layer (50) and a surface layer (51) are formed to complete the formation of the photoreceptor (46). Next, a test example in which film formation was actually performed based on this example will be described. [Test Example 1] An aluminum drum-shaped substrate (28) with a diameter of 80 mm and a width of 350 nw+t, which has been subjected to acid treatment, alkali treatment, and sandblasting treatment to prevent interference if necessary, is placed in a reaction vessel (27). ) into the reaction vessel (2
7) was evacuated to a degree of vacuum of about 10" [l~L]. Next, the heater (30) was used to heat the ram-shaped substrates (28) 1~2.
Heated to 50 [℃] and heated to 1.0 [℃] by motor (31).
r, p, m,], silane gas [5i11
4:l to 500 (SCCMI, diborane gas [B2I
+,] to silane gas [SiH,] at a flow rate ratio of 10
-', methane gas (C114:l 1001:SCCM
) into the reaction vessel (27), and the pressure inside the reaction vessel (27) was reduced to 1 cI using an exhaust device (not shown).
- while maintaining the
A high frequency power of 0 [W:] is applied between the ram-shaped substrate (28) and the cylindrical electrode (36), and p-type (a-5iC
A charge injection prevention 11-layer (47) having a thickness of 0.3 m (4 m) and consisting of: H) is formed. Next, the reaction vessel (
27) The flow rate of diborane gas (B21+,) relative to the silane gas [5ift4] in the drum-shaped substrate (28) was set to 10-7, and the methane gas [CH4] was stopped.
and the high frequency power between the cylindrical electrode (36) is 1 (KW:
A charge transport layer (48) consisting of a ■-shaped (a-5j, : I-I) with a charge injection prevention layer (47)-
1-, a film is formed until the film thickness becomes 20 [μm]. After this, without changing other film forming conditions, first lower the high frequency power to 998 (W'l) of 50 [people] (a-3i:I(
) is formed as a barrier layer (50a) of the charge generation layer (50), and then high frequency power is applied to 1 [K11. Return to l,
It consists of (a-3j:H) of 50 [human], the hydrogen content is 12 [%], and the optical band gap is 1.68 [e
The well layer (50b) of the charge generation layer (50) of V) is formed, and the high frequency power is further lowered to 996 [W].
50 [people] of a) are formed, and the high frequency power is returned to 1 [K], and 50 [people] of the well layer (50b) is formed. Then, in this way, the high frequency power was lowered by 2 [W] until it reached 5 (to (W'l)).
a-3i: Barrier layer (50a) consisting of T-T
and high frequency power] [K11] 50 [people]
250 well layers (50b) consisting of (a-3j:I()) were alternately formed to form a charge generation m (50) of a heterojunction superlattice structure with a thickness of 2.5 CI 1 m'l. In the barrier layer (50a), as the film-forming special high frequency power is lowered from 9981:W) to 500[W:l], the hydrogen content decreases from about 12% to about 30%. %
], and the optical pan 1 is increased as shown in Figure 3 (a).
~The gap is from about 1.68 [eV] to about], 8 (e)
will be increased to After this, finally, 250 [:SCCM'l] of silane gas (S]H,,:l
, methane gas (C14,) was introduced at a flow rate of 2000 ESCCM), and while maintaining the pressure inside the reaction vessel (27) at 1 [1~L], high frequency power of 1 [KW] was applied, and (a - 5ic: Film thickness consisting of H) 0.5 [μm]
A surface layer (51) is formed to complete the production of the photoreceptor (46). Approximately 500 photoreceptors (46) were prepared in this way (11).
When positively charged with (V) and exposed to white light, a large number of electron-hole pair carriers are generated, and the carriers have a long lifespan and high running properties, making it possible to actually copy the photoreceptor (46). When attached to the machine and image formation was performed, a clear and high quality image was obtained, and the image reproducibility and stability due to repeated charging were also good.Furthermore, it had good adhesion, corona discharge resistance, and moisture resistance. It was found that the material was excellent in durability such as wear resistance and abrasion resistance.
Test Example 1] charge generation 7m (50) barrier layer (50a
) hydrogen content is 30 [%], that is, the band gap is 1.
81: eV:l is constant, and the hydrogen content of the well layer (50b) is 7 [%], that is, the band gap is 1.571: eV.
). That is, in the same manner as [Test Example 1], the drum-shaped substrate (28), J2, 0 and 3 [
l1m 'J charge injection prevention layer (47) and 20[I
A charge transport layer (48) of Jm] is formed. Thereafter, the high frequency power was increased from 1.002 [W] to 1.500 (W:l) in 2 [W] increments to form a film of 50 (a-
5i:) A well layer (50b) consisting of I) and 50 [people] (a-5i:) formed into a film with high frequency power of 1000 [W].
250 barrier layers (50a) consisting of H) were formed alternately, and a charge generation layer (50) having a heterojunction superlattice structure with a thickness of 2.5 [μm] was formed. Example 1] A surface layer (51) of 0,51:7xm] was formed in the same manner as in Example 1. The photoreceptor (46) thus obtained has high spectral sensitivity even to long wavelength light of 780 to 790 [μm], which is the oscillation wavelength of a semiconductor laser, and is actually a semiconductor.
When it was attached to a Subbeam printer and image formation was performed, it was possible to obtain a clear, high-resolution image with no fogging or crushed type. Furthermore, when this photoreceptor was repeatedly charged, the transferred image had high reproducibility and stability, and had excellent durability such as corona resistance, moisture resistance, and abrasion resistance. With this structure, the charge generation layer (50), which is a part of the photoconductive layer, alternately laminates barrier layers (50a) and well layers (50b) whose band gaps are continuously varied for each layer. Because the charge generation layer is formed from a superlattice structure (a-3i:H), the number of carriers generated by light irradiation is larger than that of a single layer, resulting in high spectral sensitivity. In addition, the carrier has excellent running properties, has a long life, and has excellent photoconductive properties.Furthermore, the barrier layer (50a) maintains the optical hand gear above a certain level, resulting in low resistance. Since there is no charge, it is possible to obtain high spectral sensitivity over a wide wavelength range from the visible light region to the near-infrared hit/miss range, making it possible to apply it to semiconductor laser beam printers. Clear, high-quality images can be obtained without blurring or fogging. Note that the present invention is not limited to the above-mentioned embodiments and can be modified in various ways. For example, the photoconductive layer is not separated into a charge generation layer and a charge transport layer, but has a structure like (Example 1). may exist, and constitute a superlattice structure (a-3i:I()
There are no limitations on the film thickness, the number of layers, or the hydrogen content, that is, the size of the gap, and by adjusting these, it is possible to obtain a photoreceptor with optimal photoquaternary characteristics for light of any wavelength. It becomes possible. Further, the amount of variation in the band gap for each layer of the barrier layer and the well layer is arbitrary, and the high frequency power may be varied by 1 [W] at the time of film formation, and the form of the variation in the band gap can also be changed as follows: If the boundary between thin layers having different optical bandgaps is formed, the modification example [1st modification example] to the fifth modification example shown in FIGS. In the second modification, the well layer (60b) is kept constant and the band gap of the barrier layer (10a) is gradually decreased, and in the second modification, the barrier layer Ji (16a) is
) may be kept constant and the gaps 1 to 1 of the 5-well layer (41, b) may be gradually increased, or even the barrier layers (62a), (6
3b) and the well layers (62a) and (63b), or, as in the fifth variant, increase the gap of the barrier layer (64a). While increasing the number after decreasing it once,
The hunt gap of the well layer (64b) may be increased once and then decreased. Furthermore, the material of the thin film may contain at least one of carbon [C], oxygen [○], and nitrogen CNI to adjust the optical band gap, or it may contain a material according to the periodic table due to carrier mobility. It is also possible to contain an element of Group TII or Group Ⅰ. Note that the change in hydrogen content in the superlattice structure, that is, the change in band gap, does not have to be linearly continuous; for example, in [Test Example 1],
During the formation, the high frequency power was not immediately switched between forming the barrier layer (50a) and the well layer (50b), but the high frequency power was continuously returned from 998 [W) to 1000 [W], and then again to 996 [W]. :], and the band camp in the superlattice structure varies in a curved manner between the barrier layer (66a) and the well layer (66b) as shown in the sixth modification shown in FIG. You can do it like this. [Effects of the Invention] As explained below, according to the present invention, the material has excellent durability, has a long life, is non-polluting, and does not require collection after use. (a-5j,:H) type material is used for the photoconductive layer, and it has high spectral sensitivity over a wide wavelength range from visible light to near-infrared light, and is particularly excellent for long wavelength light. A light that exhibits photoconductive properties, does not have low resistance like conventional methods, has excellent charging properties, can obtain clear and high resolution images, and can be applied to laser beam printers, etc. A conductive member can be obtained.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic explanatory diagram showing a film forming apparatus thereof, FIG. 2 is a partial sectional view showing the photoreceptor, and FIG. 3 (A). Graph showing part of the energy band of the charge generation layer of the bass [on the test side], 3rd
Figure (B) is a graph showing part of the energy band of the charge generation layer of [Test Example 2], and Figures 4 to 9 illustrate the principle of the present invention and show the photoreceptor of (Specific Example 1). 5 is a partial sectional view showing the photoreceptor of (Specific Example 2), FIG. 6 is an enlarged sectional view of a part of FIGS. 4 and 5, and FIG. A graph showing part of the change in hydrogen content in the photoconductive layer of (Specific Example 1) or the charge generation layer of (Specific Example 2), FIG. Figure 9 is a schematic diagram showing the energy gap of (Specific Example 2).
0 (a) to 10 (e) are graphs showing part of the energy bands of the charge generation layer of the first to fifth modifications, and FIG. 11 is a graph showing charge generation of the sixth modification. It is a graph showing a part of the energy band of a layer. 26 glow discharge device, 27 reaction vessel, 28
drum-shaped base, 32-support rod, 34 high-frequency power supply, 36 cylindrical electrode, 37a, 37n, gas cylinder, 38 gas supply system, 46...photoreceptor,
47・Charge injection prevention layer, 48 Charge transport layer,
50. Charge generation layer, 51.. Surface layer, 52
...Photoconductive layer. Agent: Patent Attorney Norio Ogo +6 2nd illustration: Furu. a 4th figure / pu oa including i d 2 - ro 5th fig. −−−−■−−−□□Hot■
■■■--b■--■-1,,-111,,,,,1 Figure 10 (C) Film thickness Figure 10 (E)

Claims (1)

[Claims] In a device having a charge injection prevention layer and a photoconductive layer on a conductive support, at least a part of the photoconductive layer is a superstructure in which a large number of barrier layers and well layers made of thin layers of amorphous silicon-based semiconductor are laminated. A photoconductive member comprising a lattice structure, wherein the hydrogen content of the barrier layer and/or the well layer varies continuously from layer to layer.