JPS6194054A - Photoconductive member - Google Patents

Abstract

PURPOSE:To form a photoconductive member which has no residual potential and has excellent electrostatic chargeability by forming a charge implantation preventive layer on a conductive base body and forming the 1st photoconductive layer consisting of amorphous silicon and the 2nd photoconductive layer consisting of amorphous silicon carbide thereon. CONSTITUTION:The charge implantation preventive layer 12 consisting of the P or N type amorphous silicon carbide is formed on the conductive base body 11. The 1st photoconductive layer 13 consisting of the amorphous silicon having 0.1-5.0mum film thickness is formed thereon. The 2nd photoconductive 14 consisting of the amorphous silicon carbide is further formed thereon. A surface layer 15 is formed thereon, by which the photoconductive member 10 is obtd. The group IIIa or Va element of periodic table may be incorporated into the layer 12. Since the photoconductive member 1 has the 1st and 2nd photo conductive layers, said member has the excellent electrostatic chargeability and charge holding power and the life thereof is extended.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to 1) the use of light (electromagnetic waves such as ultraviolet rays, visible rays, infrared rays, ).

[Technical background of the invention and its problems] In general, the photoconductive material constituting the photoconductive layer has a high resistivity in the dark, usually 1013 Ω or more, due to the purpose of its use, and its resistivity is high when irradiated with light. It must have properties that reduce resistance.

For example, to explain the principle of electrophotography and the conditions necessary for a photoreceptor, when light is irradiated onto the surface of a photoreceptor that has been charged by raining charges due to corona discharge, pairs of electrons and holes are created, and either On the other hand, the charge on the surface of the photoreceptor is neutralized (1) For example, if it is positively charged, it is neutralized by pairs of electrons and a positively charged latent image is formed on the surface of the photoreceptor, which is visualized. This is done by attracting black powder (developer) called toner, which is charged with the opposite sign to the charge on the surface of the photoreceptor, to the surface of the photoreceptor using Coulomb force. In order to prevent the developer from being attracted to the surface of the photoreceptor due to the charge of the agent, a process of increasing the potential of the developer so that an electric field in the opposite direction to the electric field due to the charge is generated between the photoreceptor and the developer ( Hereinafter, this will be referred to as a developing via.

In the principles of electrophotography, the photoreceptor and the following conditions are required: first, the charge must be charged by corona discharge and maintained until the time of light irradiation; For example, one electron and hole pair neutralizes the charge on the surface of the photoreceptor 1,1 without recombining, and the other one instantly reaches the support of the photoreceptor.

Conventionally, amorphous chalcogenide-based materials have been used as this type of photoreceptor material.

However, although amorphous chalcogenide can be easily made into a large area and has excellent photoconductivity, it has a light absorption edge from the visible to near the ultraviolet range, so it is practically not sensitive to light in the visible range. Not only does it have a low hardness, but it also has problems such as a short life when applied to electrophotographic photoreceptors.

Therefore, as a photoconductive material that has recently attracted attention, there is amorphous silicon C (hereinafter abbreviated as a-8i).

The above-mentioned a-8i has a wide light absorption wavelength range and has an orthochromic property (
Panchromatic), not only has a high gap and high hardness, it is also harmless to the human body, and compared to single crystal silicon,
In this case, it has many advantages, such as being able to obtain a large-area product at low cost and expected to have a lifespan of 10 times longer than conventional amorphous chalcogenide-based products.

However, the drawback of a-8i is that the specific resistance in the dark (hereinafter referred to as
(referred to as dark resistance) is usually low, around 108 to 10,100m, and in devices that form electrostatic latent images, such as electrophotographic photoreceptors, there is a problem in that the photoreceptor surface cannot retain the electric charge. .

The means to solve this shortcoming of the a-8i are as follows:
Between the photosensitive layer and the support, N (nitrogen), C (carbon), 0 (
A-8i layer with high resistivity added with oxygen) etc. is interposed 1
-, , make it possible to block the injection of carriers from the support, or form this layer with a P-type or n-type semiconductor film (however, in the case of positive charging, the magnetons should be blocked by blocking 1). ~.

Attempts have been made to use a P-type semiconductor through which holes can pass, and to use an N-type semiconductor in the case of negative charging.However, although these methods increase the charging ability of the photoreceptor, in the former case, When the film thickness is increased, the passage of carrier flowing from the photosensitive layer to the support is also t! As a result, a problem arises in that the residual potential becomes high, and if the film is thin, dielectric breakdown may occur due to the developing bias. On the other hand, in the latter method, the problem like the former does not occur even if the thickness of the semiconductor film is increased, but ordinary amorphous silicon has a low resistivity and cannot obtain sufficient charging ability. There is a problem in that images tend to be blurred due to the lateral diffusion of carriers caused by exposure.

[Purpose of the invention]

The present invention has been made under the above circumstances, and an object of the present invention is to provide a photoconductive member that has no residual potential, has excellent charging ability, and has a long life.

[Summary of the invention]

In order to achieve the above object, the present invention provides a photoconductive member in which a charge injection prevention layer and a photoconductive layer are sequentially laminated on a conductive substrate, in which the charge injection prevention layer is formed of amorphous silicon carbide. 1-1 If the film thickness is 0.1 μm or more, 5
．． It is characterized in that a first photoconductive layer made of amorphous silicon of 0 μm or less and a second photoconductive layer made of amorphous silicon carbide are sequentially laminated.

[Examples of successful inventions]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in the drawings.

As shown in FIG. 1, IO in the figure is a photoconductive member obtained by a manufacturing process described later. The photoconductive section 4-4. Io
A charge injection prevention layer I2 made of P-type or n-type amorphous silicon carbide doped with B (boron) or P (phosphorus) (-5) is laminated on a conductive substrate II, and then Amorphous silicon (a
-8i), and a second photoconductive layer I4 made of amorphous silicon carbide is sequentially laminated thereon. On top of the photoconductive layer I4 of 2 is a surface coating @I5 selected from either amorphous silicon oxide or amorphous silicon nitride or amorphous silicon oxide at 500A-
The layers are preferably laminated with a film thickness in the range of 5 μm.

That is, in order to manufacture the photoconductive member IO described above, the conductive substrate II is placed in a vacuum reaction chamber (not shown) from 1 to 10-', and the reaction chamber is heated from 10-1 to 10-' by a mechanical booster pump and an oil rotary pump (not shown). Make a vacuum of Torr. At this time, the substrate II is heated to maintain a moist range of 100 to 400°C. Next, a gas containing Si (silicon) atoms, for example 8i, is introduced into the reaction chamber.
H.

Introduce a gas such as 8i, H6 or S i F, and
．． Adjust the pumping speed so that the pressure is about 1 to 1, Q Torr. When the inside of one reaction chamber is in a steady state, a high frequency power of 13.56 MHz is applied between the electrodes in the reaction chamber to form an a-8+ layer on the substrate II. In this case, a-8i
It is possible to control the valence electron side a'+ and specific resistance by doping with Group IIIa and Group Va of the periodic table of elements, and further by adding N (nitrogen), C (carbon), and 0 (oxygen). The resistivity becomes high. In addition, the method of adding impurities is
This can be easily achieved by matching the gas containing 81 atoms with the additional gas in the reaction chamber during film formation.

Next, to explain the function of the photoconductive member according to the above-mentioned l-octopus invention, the charge injection prevention I@1 laminated on the base 11
Since the second layer is made of amorphous silicon carbide, it can overcome the disadvantage of the aS+ layer that doping with a large amount of B or P increases strain in the film and makes the film easy to peel off. The photoconductive layer 130a-8+ layer has disadvantages due to the use of amorphous silicon carbide in the second photoconductive layer 14, namely, amorphous silicon carbide compared to a-8i.
This is to compensate for the drawbacks of a wide optical bandgap and a narrow sensitive wavelength range. Therefore, it is sufficient for this A-8ill to have a film thickness of about 0.1 to 5.0 μm, depending on the light source used for exposure. Moreover, the second photoconductive layer I4 is
This compensates for the drawbacks of the first photoconductive layer I3, namely, that a -8+ has a low specific resistance and insufficient charging and holding ability compared to amorphous silicon carbide. , this increases the charging ability and retention ability by 20-30%.
Furthermore, by doping the first and second photoconductive layers 13 and 14 with a small amount of B, the resistivity becomes even higher than that of K, and the mobility of holes also increases. A favorable result is obtained in that it is higher than in the case without doping.

Specific example: B is present on a conductive substrate in an amount of 1 x 10-3 to 1.0 at% (a
tomic%) was deposited as a charge injection prevention layer (the film forming conditions at this time were 8i
H, versus 1. ．． Mix about 20 to 100% of CH,
Mix 1 to 10% of BtHe (@W20000ppm) to SiH).

Next, the first photoconductive layer of the a-8+ is deposited with a thickness of 0.1-5 μm (this layer is preferably doped with a small amount of B, then 8iH, whereas the He-based B
A film is formed by darkly mixing about 1 to 10% of 2H6 (9 degrees, 20 ppm). Next, a second photoconductive layer of amorphous silicon carbide was laminated [7 (this layer has CH, for 8iH,
It is the same as the first photoconductive layer except that the mixture is about 5 to 40%, and the optical band gap of the film obtained is 1.7 to 1.9 ev, which is slightly larger than that of a-8i. ). Furthermore, a surface coating layer was laminated on top of it (this layer had the same amount or more (1'
)CH,,C2H,,C,,H2,o,,N2. NH8
7. Mix and form a film. The film preferably has a darkness of about 500 A to 5.0 μIn, and the resulting optical gap of ++a becomes as large as 20 ev or more). When such a layer was laminated on a cylindrical substrate made of A/ (aluminum) and used as an electrophotographic photoreceptor, it had sufficient charging ability and charge retention ability to be used for positive charging. ,
A long lifespan was obtained with no image disturbance even after more than 100,000 copies were made.

On the other hand, P instead of B is used in the charge injection prevention layer.
When doped with , it becomes a square band heavy use, and the above-mentioned 1. Similar results were obtained.

rEffects of the Invention] Above Explanation J ~ According to the present invention, a charge injection prevention layer made of amorphous silicon carbide and an ultrathin layer made of amorphous silicon (a-8i) are formed on a conductive substrate. Since it has a structure in which the first photoconductive layer and the second photoconductive layer made of amorphous silicon carbide are laminated in sequence, the charging ability and It is possible to provide a photoconductive member with excellent charge retention ability and long life, and when used in an electrophotographic photoreceptor or the like, it exhibits great effects.

[Brief explanation of the drawing]

The drawings are schematic explanatory diagrams showing one embodiment of a photoconductive member according to the present invention. 10... Photoconductive member, II... Conductive substrate, 12.
...Charge injection prevention layer, I3...First photoconductive layer, I
4... Second photoconductive layer, 15... Surface coating layer.

Claims (4)

[Claims] (1) In a photoconductive member in which a charge injection prevention layer and a photoconductive layer are sequentially laminated on a conductive substrate, the charge injection prevention layer is formed of amorphous silicon carbide, and a film thickness of 0.000 mm is formed on the charge injection prevention layer. 1
A photoconductive member characterized in that a photoconductive layer made of amorphous silicon with a size of 1 μm or more and 5.0 μm or less and a second photoconductive layer made of amorphous silicon carbide are sequentially laminated. (2) Claim 1 characterized in that the charge injection prevention layer and the first and second photoconductive layers contain an element from Group IIIa or Group Va of the Periodic Table of Elements. The photoconductive member described. (3) A surface coating layer having a larger optical bandgap than that of the second photoconductive layer is laminated on the second photoconductive layer. The photoconductive member described. (4) The photoconductive member according to claim 3, wherein the surface coating layer is made of any one of amorphous silicon carbide, amorphous silicon nitride, or amorphous silicon oxide. .