JPH01295264A - 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 superlattice structure obtained by repeating lamination of microcrystalline silicon type plural thin layers. CONSTITUTION:The electric charge generating layer 50 of a part of a photoconductive layer is made of the microcrystalline silicon muc-Si:H of superlattice structure formed by alternately laminating first thin layers 50a and second thin layers 50b different in the band gap in each layer, accordingly, the layer 50 generates many carriers by irradiation with light as compared with an electric 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 first layer 50a large in the optical band gap serves as a potential barrier layer, it maintains high 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] (Field of Industrial Application) 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 (ZnO3, and selenium [Se]) have been used as photoreceptor materials.
, selenium tellurium alloy [inorganic materials such as 5e-Te3, poly-N-vinylcarbazole (hereinafter referred to as PVCz)]
A variety of organic materials have been developed, including organic materials such as , trini-1 to rofluorene (hereinafter referred to as TNF). However, among the photoreceptor materials, selenium 1:Se]
, cadmium sulfide (CDS), etc. are essentially harmful materials to the human body, so the manufacturing equipment becomes complicated for safety reasons during manufacturing, increasing manufacturing costs, and they cannot be recovered after use. This has a negative effect on the cost, leading to an increase in price, and also because selenium [Se:l and selenium-tellurium alloy [5e-Te3] have a low crystallization temperature of about 65 ['C]. Because it has, it is easy to crystallize,
During repeated copying, a residual charge is generated in the crystallized portion, which tends to cause problems such as staining the image, and ultimately has the disadvantage that a long service life cannot be achieved. and zinc oxide [
Due to its physical properties, ZnO3 is susceptible to oxidation-reduction and is significantly affected by environmental conditions such as temperature and humidity, resulting in unstable image quality and poor reliability. Furthermore, organic materials such as (pVCz) and (TNF) have poor thermal stability and wear resistance, which makes it difficult to extend their service life, and recently they have been suspected of being carcinogenic. Therefore, in recent years, as a solution to the above-mentioned drawbacks, it is non-polluting, does not require recovery treatment, has a high surface hardness, has excellent abrasion resistance and impact resistance, and has higher spectral sensitivity than before. amorphous silicon (hereinafter referred to as a-3i)
: Called H. ) are being considered for application to photoreceptor materials. That is, specifically, since the photoreceptor is required to have high resistance and high spectral sensitivity as its characteristics, in order to satisfy both of these characteristics, a conductive support and (a-5i: l(
) A laminated type (a-5i:
H) A photoreceptor has been developed. However, (a-5i: H) is silane [S1]
When forming a film using a glow discharge decomposition method using a gas containing (a-3J: H), hydrogen atoms [
)() has the problem that the electrical properties and optical properties vary greatly depending on the amount of (a-
5]: 11) As the amount of hydrogen atoms incorporated into the film increases, the optical punt cap 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. S
Bonds with bond structures such as iH,)n] bonds and (S, +, l+2) bonds become dominant in the (a-3i:H) film, and as a result, the [SiH] bonds are cleaved, resulting in dangling. There is a problem that structural defects such as ring bonds and voids increase, and photoconductivity deteriorates. On the other hand (a-3j:
H) As the amount of hydrogen atoms [11] incorporated into the film decreases, the spectral sensitivity to long wavelength light increases;
The optical bandgap becomes smaller and the resistance becomes lower, and the hydrogen atoms [11] no longer compensate for the dangling bonds, so the mobility and lifetime of the generated carriers decreases, and the photoconductivity also deteriorates. However, there is a problem in that it cannot be used for photoreceptors. (Problems to be Solved by the Invention) Conventionally, the spectral sensitivity characteristics or resistance values, etc. of (a-5i: 11) conflict with each other depending on the variation of the hydrogen content in the (a-3j: H) film. It has excellent optical and electrical properties (a-5j:
H) It is not possible to obtain a photoreceptor, resulting in a problem of deterioration of image quality. Therefore, the present invention solves the above problems by using a non-polluting semiconductor with high surface hardness, and maintaining high resistance.
In addition to obtaining excellent charging characteristics, it also has high spectral sensitivity characteristics over a wide wavelength range, making it possible to obtain clear and high-quality images even with laser beam printers, etc. Furthermore, it has good adhesion to substrates and is durable. The purpose is to provide a photoconductive member with excellent environmental friendliness. [Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method in which the crystallinity of at least a part of the photoconductive layer is varied at a period of 30 to 200 [persons]. Multiple microcrystalline thin layers
It has a superlattice structure that is repeatedly laminated. (Function) The present invention improves photoconductive properties over a wide wavelength range and prevents deterioration of spectral sensitivity characteristics and charging characteristics against long wavelength light by the above means, thereby making it suitable for laser beam printers and the like. This makes it possible to apply it. (Example) In explaining the present invention in detail, the characteristics of microcrystalline silico (hereinafter referred to as μC-3i:H) and the superlattice structure which is the principle of the present invention will be described. First, (μC-3i: l()) has a smaller optical bandgap than (a-3i: H), has sensitivity in the long wavelength region near the near-infrared region, and has fewer structural defects. That is, this (μC-5,i: H) belongs to non-single crystal silicon, but when X-ray diffraction measurements are performed, (a-3i: H) is amorphous as shown by the fourth dotted line. Therefore, only a halo appears and no diffraction pattern is observed, whereas (μC-5i: H) has a crystal diffraction pattern in the vicinity of [20] of 78 to 28.5 degrees, as shown by the solid line in Figure 4. On the other hand, polycrystalline silicon has a dark resistance of 106 [Ω・c+n] or less, whereas (μC-3i: H) has a dark resistance of 10” [:Ω・Cm].
] or higher dark resistance. Due to the above-mentioned characteristics, (μC-5i: H) is distinguished from other non-single-crystal silicon (a-5i: H) and polycrystalline silicon, and its structure is similar to that of about several dozen people. It is thought that it is formed by aggregation of microcrystals with a particle size. To produce such (μC-3i: H), sputtering, glow discharge decomposition, etc. are used in the same way as (a-5i: l+), but (a-5j:
H) Formation becomes easier if the temperature of the conductive support on which the film is formed is set higher than during manufacturing, or if the high frequency power is increased. That is, by raising the temperature of the support and increasing the high-frequency power, the raw material silane [Sj
] This is because the flow rate of the contained gas can be increased, and as a result, the film formation rate is increased and (μC-3i:H) is more likely to be formed. Furthermore, hydrogen [H
] When using a gas diluted with (μC-5i: 14
) can be formed more effectively. Furthermore, in order to improve the photosensitivity characteristics and increase the resistance, (
In addition to hydrogen atoms [1], impurities are doped into the μC-3j: H) layer, and as with (a-8i: H) described later, in order to make it p-type, the impurity element is Elements from Group 1 of the Periodic Table are suitable; on the other hand, elements from Group 2 of the Periodic Table are suitable for making the material n-type. Also (μC-3
In order to increase the dark resistance of i:H) and improve the photoconductive properties, it is desirable to dope with at least one of nitrogen (N), carbon (C), and oxygen [O]. In this way, these elements become (μC-3j: H
) and acts as a terminator for dangling bonds of silicon (Si:l), reducing the density of states existing in the forbidden cloth between bands. Due to such characteristics, if (μC-5i:H) is used in the photoconductive layer of a photoreceptor, it becomes possible to increase the spectral sensitivity in the long wavelength region near the near-infrared region. Next, we will discuss the superlattice structure. That is, it may be either crystalline or amorphous, but it has a very small thickness of about 30 to 200 mm.
In a semiconductor layer consisting of a stack of multiple thin layers with different optical bandgaps, the one with a relatively smaller optical bandgap is A superlattice structure having a periodic potential barrier is formed in which the layers are well layers and the layer with a relatively larger optical bandgap is a barrier layer. In this superlattice structure, since the /< rear layer is extremely thin, carriers easily pass through the barrier layer due to carrier tunneling effect in the thin layer, and are accelerated by the electric field in the superlattice structure. It runs in the superlattice structure with high running performance compared to the above. 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. 5 to 10, and in the (specific example) shown in FIG. An injection prevention layer (11) is formed;
A photoconductive layer (12) and a surface layer (13) are formed on the charge injection prevention layer (11). Also, as shown in Figure 6 (
Specific example 2) is the same as specific example 1, in which the photoconductive layer (12) is functionally separated into a charge generation layer and a charge transport layer, and includes a conductive support (10) and a charge injection prevention layer (11). )
A charge transport layer (16) is formed thereon. A charge generation layer (17) is formed on the second side of this charge transport layer (6), and a surface Jil (17) is formed on the charge generation layer (17).
13) is formed. In (Specific Example 1), the photoconductive J* (12) generates carriers upon incidence of light, and one polarity of these carriers neutralizes the charges on the surface of the photoreceptor, and the other polarity The thing is photoconductive! (12) to the conductive support (10). 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 ( 10). When the photoconductive layer (12) or charge generation layer (17) in these (specific examples) is enlarged, it becomes as shown in FIG. 7, and the optical band gap is different, and the thickness of each is 30 mm
[person] to 200 [person] first (a-3j: 1
1) layer (18) and second (a-5i: t() layer (
It has a superlattice structure in which 20) are alternately laminated. For example, the j-th (a-3i: H) M(18) has a hydrogen content of 30 [%], and the second (a-5j:
ION (20) has a hydrogen content of 12%, and the 8th
As shown in the figure, the photoconductive layer (12) or the charge generation layer (
17), the maximum optical punt cap of the first (a-3i:l() layer (18) is 1.8 [eV] and Since the minimum optical band gap of the (a-3j: t+) layer (20) of 2 is 1.68 (eV), the energy band diagram in the thickness direction in the superlattice structure is as shown in Figure 9. , the (a-5i : H) layer (18) of the second (a-3i : t(
) JW (20) becomes a potential well, and potential barrier layers and well layers are periodically formed. Furthermore, each layer of the superlattice structure (18), (2
By changing the optical bandgap or layer thickness of layer 0), the apparent bandgap of the layer having a heterojunction superlattice structure can be freely adjusted. In addition, materials that form such a superlattice structure have a hydrogen content of 30 [atomic%] and a band gap of 1.8.
(eV), hydrogen content is 12 [atomic %], band gap is 1.68 [eV: 1 etc. (a-3i: t() or optical pan 1 ~ increase gap to 1.9 (eV) Nitrogen [N], carbon [C], oxygen

[0] Amorphous silicon nitride (hereinafter referred to as a-3iN:
It is called H. ), amorphous silicon carbide (hereinafter a-5
jC: Referred to as H. ), amorphous silicon oxide (hereinafter referred to as a-3iO: H), etc. (a-3i: II
) system, or the above-mentioned optical pan 1 to gap 1,
5 [eV] or higher (μC-3j: H) or microcrystalline silicon carbide (hereinafter μC-3) N:
It is called H. ), microcrystalline silicon carbide (
Hereinafter referred to as μC-5iC: It. ), microcrystal phosphorylated silicon (hereinafter referred to as μC-5i○:H)
etc. (μC-5j, :H) system, which generally exhibits weak n-type when undoped, and contains boron [B], alumina 1. (By increasing the doping of elements in Group II of the periodic table such as AQ, 1, etc., the l-type changes to p-type, whereas phosphorus CP), nitrogen [N], etc. in group II of the periodic table By increasing the doping of group elements, n-type characteristics become more pronounced. Furthermore, by doping with an element of Group 1 or Group 2 of the periodic table, the mobility of carriers is further improved. In addition, as other materials, optical huff 1-cap is 1
．． 5 [eV] amorphous germanium silicon (hereinafter referred to as a-3iGe: t+), amorphous germanium nitride (hereinafter referred to as a-GeN:H),
Amorphous germanium carbide (hereinafter a-GeC:
It is called H. ), amorphous germanium oxide (hereinafter a)
-GeO: Referred to as H. ) etc. Also, optical pan 1
~Not only for cap fluctuations, but also for these materials, to compensate for the dunking bond of silicon, balance dark resistance and bright resistance, and improve photoconductivity. It is desirable that hydrogen [H] contains 0.01 to 30 [atomic %] gold. And for example (a-3i
: When forming a thin layer of H) or (μc-5j:H) by the claw discharge decomposition method, silane gases such as silane [SiH,] and disilane (S'', 2) 1c) are used as raw materials. H can be added into the thin layer by introducing it into a reaction chamber and performing tallow discharge with high frequency. On the other hand, (a-5j, N: old or (μC-5iN: H
), it is sufficient to add a required amount of nitrogen gas [N2] or ammonia gas (I:NH3) or the like to the raw material gas. Furthermore, (a-3]Ge:H) is usually silane (Si
The film is formed by glow discharging a mixed gas of H4) and germane (Ge14). If necessary, hydrogen gas (1121) or helium gas (He) can be used as a carrier gas for silanes. On the other hand, silicon tetrafluoride [SiF4] gas and 1-lichlorosilane (:
Silicon halides such as 51C14:1 gas can also be used as source gas. In addition, even if the reaction is performed with a mixed gas of silane gas and silicon halide gas, (a-5iN: H) and (a-3i
: H), or even (μC-3iN: It). 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 (
12) 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 negatively charged, the charge injection prevention 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 a semiconductor charge injection prevention layer, (μC-3):
t+), (μC-3iN: l(), (a-3]: H) or (a-5iN: H). And (μC-3i: H) and (a-3j: H) etc., in order to make them p-type, elements belonging to Group Ⅰ of the periodic table, such as boron [Bj, aluminum [A]], gallium [Ga], indium (I
n), and thallium [T1], etc., and (μC-3j: H) and (a-Sj:
In order to make H) n-type, elements belonging to Group Ⅰ of the periodic table, such as nitrogen [N], phosphorus (Pl), arsenic (As
), antimony (sb), bismuth [:Bj ], etc. are preferably 1-1 pinged. This n-type impurity or doping with n-type impurities prevents charges from moving from the support side to the photoconductive layer. On the other hand, (μc-
3j: H) and (a-3j: H), etc., carbon [C
], 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 preferably 100 [μm] to 0 [μm]. Furthermore, in (Specific Example 1) and (Specific Example 2), the photoconductive layer (12) or the charge generation layer (17) l,
The surface layer (13) is provided for the following reason. That is, (a-3j) of the photoconductive layer (12) or the charge generation layer (17)
: 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. Also, by providing the surface layer (13), the photoconductive 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-3iN:H), (a-5
iO: H), and (a-5iC: II), (p C
-3iN: H), (p C-5iC: H), (μ
These include inorganic compounds such as C-8iO: H) and organic materials such as polyvinyl chloride and polyamide. When the surface of the photoconductive member constructed in this way is charged with a positive voltage of approximately 500 V (l) by corona discharge, it becomes, for example, the functionally separated type shown in FIG. 5 (Example 2). As a result, a potential barrier as shown in Fig. 10 is formed.When light (hν) is incident on this photoconductive member,
Carriers of electrons (21) and holes (22) are generated by the superlattice groove structure of the charge generation layer (17). Electrons (21) in the conduction band are accelerated toward the surface N (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. 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 the superlattice structure,
Although a periodic barrier layer is formed due to bandgap discontinuities, carriers easily pass through the bias layer with a one-Hennell effect, so the effective carrier mobility is equivalent to that in the bulk. Excellent running performance. As described below, a photoconductive member having a superlattice structure in which thin layers with different optical band gaps are laminated can obtain high photoconductive properties and produce clearer images than conventional photoreceptors. be able to. 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 (2
6) Inside the reaction vessel (27) is a conductive support,
In order to support the drum-shaped base (28) made of aluminum, a support rod (32) has a built-in heater (30) and is rotated by a motor (31) via a shaft (31a).
A support stand (33) for supporting this support body (32) is provided. Also, the circumference of the support (32) is 13.56
(MHz) is connected to a high frequency power source (34) and is surrounded by a cylindrical electrode (36) supported on the bottom (27), and above the support (32) is a silane gas [
A large number of gas cylinders (37a
)...(37n) and a gas supply system (38) having a gas mixer (38a) is provided with a gas introduction pipe (40) connected via a gas introduction valve (40a). still(
4] a) - (41n) is each gas cylinder (37a) -
Valve (37n) and (42a)-(42n) are pressure gauges. Furthermore, (43) is an exhaust valve connected to an exhaust device (not shown) that exhausts the inside of the reaction vessel (27), and (44) is a vacuum word 1 that measures the atmospheric pressure inside the reaction vessel (27). be. Further, (46) is a photoreceptor such as a laser printer which is a photoconductive member, and a charge injection prevention layer (47) and a charge transport layer (48) each having a different degree of crystallinity are formed on a drum-shaped substrate (28). (μC-5i: H) with an arbitrary thickness,
A charge generation layer (50) and a surface layer (51) having a beterojunction superlattice structure are stacked alternately and repeatedly. Note that (52) is a charge transport layer (48) and a charge generation layer (50).
) is a photoconductive layer consisting of When forming the photoreceptor (46) in the glow discharge device (26), after placing the tram-shaped substrate (28) on the support (32), the interior of the reaction vessel (27) is heated to 0.1 (1 The exhaust valve (43) is opened to bring the pressure to a level below 1.2 mm, and the exhaust gas is treated by the exhaust device (not shown), and the drum-shaped base (28) is heated to a predetermined temperature by the heater (30). 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 required 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 the power constant within a range of approximately 100 torr.
A charge injection prevention M (47) is formed on the drum-shaped substrate (28). Next, the charge transport layer (48), charge A 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 mm, which was subjected to acid treatment, alkali treatment, and sandblasting treatment to prevent interference, if necessary.
was placed in the reaction vessel (27), and the reaction vessel (27) was evacuated to a degree of vacuum of about 10-'f:l. Next, the drum-shaped substrate (28) is heated to 250°C by the heater (30).
) and heated to 10 (r, p, m,
), 500 (SCCM, l,
Diborane gas [B2H6:l to silane gas [5jH4:
Flow rate ratio to l is 10-6, methane gas f: cH4]
was introduced into the reaction vessel (27) at a flow rate of 10100 (SCC), and the reaction vessel (27
) while maintaining the pressure at 1 [1 her], a high frequency power of 500 [W] is applied between the drum-shaped base (28) and the cylindrical electrode (36) by the high-frequency power supply (34), and the p-type A charge injection prevention layer (47) made of (a-5iC: II) with a thickness of 0.3 (μm) is formed. Next, diborane gas (B2t (6 ) was set to 10-7, the methane gas [CH4] was stopped, and the tram-shaped base (28
) and the cylindrical electrode (36).
I], and a U-shaped charge transport layer (48) made of (a-3j: II) is placed on the charge injection prevention layer (47) to a thickness of 2
The film is formed until it reaches 0 [μm]. After this, without changing other film-forming conditions, only the high-frequency power was gradually and continuously raised and lowered in the range of 1200 (II) to 15001 J with a cycle of about 3 minutes, and this was repeated 500 times. By repeating this process, as shown in Figure 3, the crystallinity becomes approximately 15% at a thickness period of 50.
The crystallinity is continuously varied up to about 60%, and the optical pan 1 to gap is up to 1.63 (eV).
(μC-3i: the first layer (50a) consisting of old and high crystallinity, and the optical band gap is minimum 1, 53
The second M consisting of (μC-3j: )l) of [eV]
A charge generation layer (50) having a thickness of 5 [μm] is formed by alternately stacking 500 thin layers of (50b). Finally, silane gas [Sj, H4
] to 250 [SCCM: l, methane gas [C++41
was introduced at a flow rate of 2000 ESCCM, I, and while maintaining the pressure in the reaction vessel (27) at 1 [Torr].
k1N] is applied, and (a-3iC: t(
) with a thickness of 0.5C1zm:l is formed, and the production of the photoreceptor (46) is completed. The photoreceptor (46) thus obtained was heated to about 500 [V
) and exposed to white light, a large number of carriers of electron/hole pairs were generated, and the carriers had a long life and high running properties. When attached to a copying machine and image formation was performed, a clear, high-quality image was obtained, and due to repeated charging, the image reproducibility and stability were good, as well as good adhesion and durability. It was found that it has excellent durability such as corona discharge property, moisture resistance, and abrasion resistance. -Force photosensitive body (4
6) has high spectral sensitivity even to long wavelength light of about 780 to 790 (nm), and when it was actually installed in a semiconductor laser beam printer and image formation was performed, it did not cause fogging or crushed type. We were able to obtain clear, high-resolution images. With this configuration, the charge generation layer (50), which is a part of the photoconductive layer, is the first layer (50a) having a different band gap.
Since the thin film of the second layer (50b) is formed from a superlattice structure (μC-3j, :H) in which the thin film is sequentially and periodically laminated, the charge generation layer is different from a case where the charge generation layer is formed of a single layer. However, it has a large number of carriers generated by light irradiation, has high spectral sensitivity, has excellent carrier mobility, has a long life, and has excellent photoconductive properties.
The first layer (50a) with a large optical band gap serves as a potential barrier layer and maintains high resistance, so high spectral sensitivity can be obtained over a wide wavelength range from visible light to near-infrared light, making it suitable for laser beam printer devices. In addition, it is possible to obtain clear, high-quality images without the deterioration of charging ability that occurs in the past, resulting in blurred images 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 may have a structure as shown in (Specific Example). may constitute a superlattice structure (μC-3i
: The film thickness, number of layers, and crystallinity (band gap width) of H) are not limited, and by adjusting these, a photoreceptor having optimal photoconductive properties for light of any wavelength can be obtained. things become possible. Furthermore, the thin films for configuring the superlattice structure are not limited to two types, but three or more types of thin layers may be periodically laminated as long as they form boundaries between thin layers with different optical band gaps. It may be something. Furthermore, the material of the thin film can also be adjusted for optical bandgap adjustment.
carbon [C], oxygen

At least one of [0] and nitrogen [N] may be contained, or an element from group Ⅰ or group V of the periodic table may be contained in order to improve the transport properties of carriers. Note that the change in crystallinity in the superlattice structure, that is, the change in band gap, does not have to be continuous in a curved manner. For example, in [Test Example 1], when forming the charge generation layer (50), high frequency power is applied. , 1200[1tl] to 1.500 (12001:11] and 1.5001:su] without continuously varying in the range of ll'l), the bandgap in the superlattice structure can be changed. As in the modification shown in FIG.
A) and the well layer (60b) may be varied linearly. [Effects of the Invention] As explained above, according to the present invention, the material has excellent durability and a long service life, is non-polluting, and does not require collection after use (a-3i :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 has excellent photoconductive properties especially for long wavelength light. In addition, the present invention provides a photoconductive member that does not have low resistance as in the past, has excellent charging characteristics, can obtain clear and high-resolution images, and can be applied to laser beam printers, etc. I can do things.

[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, FIG. 2 is a partial cross-sectional view showing a photoreceptor, and FIG. Graphs showing a part of the energy band of the charge generation layer of Test Example 1], Figures 4 to 10 illustrate the principle of the present invention, and Figure 4 shows its (μc-
A graph showing the X-ray diffraction of 3j:H) and (a-3i:H), FIG. 5 is a partial sectional view showing the photoreceptor of (Specific Example 1-), and FIG. 6 is a graph showing the photoreceptor of (Specific Example 2). ), FIG. 7 is a partially enlarged cross-sectional view of FIGS. 5 and 6, and FIG. 8 is a photoconductive layer of (Specific Example 1) or (Specific Example Figure 9 is a graph showing part of the energy band of the photoconductive layer or charge generation layer 2), Figure 10 is a graph showing part of the energy band of the photoconductive layer or charge generation layer (specific example). 2) schematic diagrams showing the energy gap, FIGS. 11(A) to 11(E) are graphs showing part of the energy bands of the charge generation layers of the first modification to the fifth modification, FIG. 12 is a graph showing part of the energy band of the charge generation layer of the sixth modification. 26 claw discharge device, 77 reaction vessel, 2
8 Drum-shaped base, 32・Support rod, 34 High frequency power source, 36・Cylindrical electrode, 37a, -37
n, 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 Ogo Norifu m-” 3rd, No. 1, No. 6, No. 2, No. 100 ZOo, No. 300
3 Figure 5 Figure times, f1'r west [2θ] Figure 4 Figure 6 Figure/2. /7/ Figure 7 Figure 11 Procedural amendment form) ■, Indication of the case 1988 Patent Application No. 124910 2, Name of the invention Photoconductive member 3, Person making the amendment Relationship with the case Patent applicant ( 307) Toshiba Corporation 4, Agent 〒]-44 No. 4-41-11 Kamata, Ota-ku, Tokyo - Tsunoda Building Ogo Patent Office Tel: 736-3558 5. Date of Amendment Order: August 3, 1988 Day (starting gate August 30, 1986)
6. "Brief explanation of drawings" column of the specification subject to amendment. 7. Contents of the Amendment The phrase "Fig. 11 (A) or - a graph showing a part of it. is a graph showing part of the energy band of the charge generation layer of another modification.'' Written amendment to the above procedures (1 plow 1, Indication of the case 1986 Patent Application No. 24910 2, Name of the invention Photoconductive member 3, Person making the amendment Relationship with the case Patent applicant (307) Toshiba Corporation 4 , Agent Address: 4-41 Kamata, Ota-ku, Tokyo 144] - No. 1 - Tsunoda Building Ogo Patent Office Tel: 736-3558 5. Subject of amendment 6. Contents of amendment Br Scope of patent claims attached hereto The following should be amended. ■)■In the fifth line of page 2 of the specification box, the phrase ``It is being developed as a product.'' should be amended to read ``It is being developed as a product.'' ■In the third line of page 6 of the specification letter, the phrase ``A thin layer of silicon is corrected'' to ``A thin layer of silicon.'' ■ On page 6, line 13 of the specification, "Crystalline silicon (hereinafter referred to as") is amended to read "Blistalline silicon (hereinafter referred to as"). Above claims: At least one charge injection prevention layer on the conductive support. and a photoconductive layer, wherein the photoconductive member is characterized by the light guide H side.

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 has a superlattice structure in which a large number of barrier layers and well layers each made of a microcrystalline thin layer are laminated. A photoconductive member characterized in that the degree of crystallinity of the barrier layer and/or the well layer changes continuously from layer to layer.