JPS5957407A - Photovoltaic device - Google Patents

Abstract

PURPOSE:To transfer spectroscopic sensitive wavelength to short wavelength side without deteriorating the film quality and to prevent deterioration of photo- electric conversion efficiency caused by light irradiation for a long time, by a method wherein a layer including nitrogen and boron simultaneously is provided on a semiconductor layer of amorphous silicon. CONSTITUTION:A semiconductor layer 3 is composed of, for example, P type layer, I-type layer and N type layer in the order from a transparent electrode film 2 at light incident side. P type layer 3p is made of amorphous silicon carbide formed by glow discharge in atmosphere of silane SiH4 60% and methane CH4 40% including diborane B2H6 0.3% as doping gas. I-type layer 3i is made of amorphous silicon nitride formed under mixed gas atmosphere of SiH4 gas 80-99.99% and ammonia NH3 as nitride 20-0.01% and addition of B2H6 1%- 10ppm N type layer 3n is made of amorphous silicon formed by SiH4 gas and phosphine PH3 1% under doping.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a photovoltaic device including an amorphous silicon semiconductor layer.

(1) Prior Art Photovoltaic devices equipped with amorphous silicon semiconductor layers have already been put into practical use, and various improvements have been made. Among these improvements, cP N-junction photovoltaic devices In , type 1 (
Nitrogen INI is added to form an amorphous silicon nitride ta-8ixN1-x layer as the intrinsic layer, and the optical bandgap Eopt is lower than that of a layer that does not contain nitrogen IN+.
There is one in which the spectral sensitivity wavelength is shifted to the shorter wavelength side by increasing the wavelength.

Due to this shift to the disliked wavelength side, the PI has a different spectral sensitivity wavelength.
N-junction type light source 6, power can be placed in tandem or in 6 or more layers with 1ζ. [This (
=N In the device R, the stock "C" is beneficial.

However, as mentioned above, adding G to the I-type layer can shift the spectral sensitivity wavelength to the shorter wavelength side, but as shown in Figure 1, the Fermi level l (/ is As the layer moves closer to the conduction band and moves away from the center of the forbidden band (mid gap) EO, the ■-type layer, which had traditionally been N-type, becomes more N-type, causing the pattern to deteriorate. .

On the other hand, photovoltaic devices (2.
The generation of electron and IF hole pairs in TZ+ is not only the layer described above, but also the type 1 layer; A: It's being ignored.

Purpose of the Invention The present invention has been made to solve this problem, and its purpose is to inject nitrogen into the mold layer without deteriorating the quality.
It is possible to shift the spectral sensitivity wave to the short wavelength side by containing +. Hereinafter, an embodiment in which the present invention is applied to a PIN junction type photovoltaic device will be described in detail with reference to FIGS. 2 to 5. Showing preferred application examples of the invention
,.

(2) Embodiment FIG. 2 shows the basic structure 511 of the present invention, ([1 is a glass heat-resistant plus T-tsuku'': % (D is an insulating and light-transmitting substrate.

(21 is a transparent electrode such as tin oxide, tin oxide, etc. adhered to the -main surface of the second board (1); IΔ, (3)
is an amorphous silicon-based semiconductor layer formed on the transparent electrode 110121 by glow discharge of silane Sj-H4 gas, etc., and (4) is the semiconductor ll-'! r 1311 +:
Kure surface such as aluminum titanium superimposed on di is 14
119, if+'i, the feature of the present invention is "-
The composition of the semiconductor layer 13). That is, the semiconductor layer 1
3) is P from the transparent electrode 11”!+21 side which is the light incidence side.
Type layer (3p), I type (intrinsic) layer (3j-) and HiN'J'
J# (511) 7j111! 'l/7Jn1(1-
+4(.

He has a PIN connection Gozo, and the town has a P Bali layer (3
p) is silane S1) + 46L]% to 4[1 ~ methane CHa + 03% diborane 13 as di-doping gas
Glow 1j9′ mountain in an atmosphere containing 2 kI 6, C
Jf crystal v1 silicon carbide (a-
8ixc + -
．． S'5-H4Jf S80~99.99%, ammonino'NH which is a nitrogen compound 320~001% and B2
Amorphous silicon night wide (8,-
8:3-xN 1-x ), and tl Q
V layer (3rl is phosphine PH3 in S1-H4 Ganu)
amorphous silicon (1q′) doped to form 1
a-33-). This persimmon Kaedeji Sito I
The thickness of each of the above P-type layer (3p), I-type IN (31) and N-type 1c1 (3n) formed by glow group r(() in an atmosphere mainly composed of C,5
It is set to 0nos and 500A'.

Figure 3 shows a two-speed amorphous η silicon nitride (a
■-type layer (3
1) The movement of Fermi level E/ is diborane B2) (6
This is the gas/+f ljl ratio, that is, the result measured for the gas containing Pocon B. The mold layer (W 1.) used for this measurement was 97% S t [1a gas with 3% NHs gas added to it by varying the flow ratio of B z Hb gas and °r3 formation. It is what was done. As is clear from the figure, as the boron B content increases, the fer EL/pel Ef approaches the so-called mid gap EO, and due to the ti content 1, the N-type By adding B, which is a P-type impurity, the type layer (31) of 1 is compensated to be an intrinsic type. In this example, the 7 Hermi levels T':/Tommit' gap EO, etc. coincide, and theoretically it is true T that is Il/J
40 U p pns tear);:).

On the other hand, Figure 4 has the same specifications as Figure 6.
, 97N 0.05 of 1 type 1 jiri (3j-) - 2 photoconductivity p 11 and dark conductivity fl with respect to the diversion ratio of B z H6 gas. In the photoelectric three-power device, C is light guide/! ! Rate of ph and dark i!
It is important that the difference between the J-rate and d is large, and speaking only about the point of refusal, it is undesirable to add boron B to the mold layer (3j), and the above mold layer (3j) is At 400 ppm, which is theoretically true, the difference between d and 7-pl tends to decrease, so this difference in Sakai city rate is also taken into account.
Then, the content of B will not shrink to a certain extent at 10o p pm.
is desirable.

4D, Figure 5 is a-8'Lo, p? No, os) type 1 layer (!l1) 1: Changes in pH of normalized photoconductivity with time using B-containing bottle as a parameter at irradiation intensity of 500 mW
//! Measurements were taken when AM-1 light of j was irradiated. The sample 1al used for measurement has 1oOp of B.
p'Fj was added, and that of sample 1bl was 10
ppFFj, and sample +01 is a so-called non-doped layer that does not contain B. When B is added in this way, the change in normalized photoconductivity ty-ph over time, that is, the deterioration of photoelectric conversion efficiency, tends to be suppressed.
■Approximately 1001 considering the intrinsic compensation of the type layer (51-)
11" or more is appropriate.

Therefore, when 3% nitrogen N is added to the hollow mold layer (3i) mentioned above, 1 (t) of boron B added to the mold layer (33-) is preferably fJlooppm to 400 ppm. be.

In a more preferred embodiment, the nitrogen N and boro/B
The content of 1 in the mold layer (3i) may be maximized on the light incident side and gradually decrease by 2.

Application example Figure 6 shows boron-containing amorphous silicon nitride (a-
8>, xN 1-x ) (7) A PIN junction type first power generation region (31) having an I-type layer (31) is arranged on the light incidence side, and optical band gap E
This is a stacked photovoltaic device in which a second power generation region (32) and a third power generation region (35) having successively smaller opts are stacked. In a preferred embodiment of this end-layer photovoltaic device, the mold layer (51) of the first power generation region (31) is a T-E containing 3% nitrogen N and IQQppm boron.
Optl, 8 (eV) (Da -310,97
N O, O & Kara, 2nd departure 11 areas ift, (31
It consists of an undoped a = sj- with E o p t, 1°7 (eV), and the third emissive region (
35) is F containing 310% Sn in S, Opt,
I, 3 (eV) amorphous? / Rico / Tin (a-810
, 98n o, t ) Color tlff formation F ;h In other words, in the semiconductor power generation phenomenon, the wavelength of incident light that contributes to power generation is mainly optically prohibited by the mold layer in the emission region! 4
Depends on F width. Figure 7 shows the first and second cases in the example
．． Third power generation area (51).

(32), (3g) light absorption characteristics t51, +
61.

(7) is shown in °C. If each power generation region (31), (32'), 133) has only one optical bandgap width, then such an emission i! @J!
1li (311, (32), (35)), if sunlight etc. is incident, only light of a part of the wavelength corresponding to the optical forbidden width will emit light, and light of a shorter wavelength will contribute to the emission. The incident light energy becomes heat and dissipates within the element, and the incident light energy of long wavelengths is dissipated without being absorbed within the element. As is clear, when looking at the device as a whole, there are multiple optical bandwidths, and since the arrangement is such that the bandwidth decreases from the light incident side to Ill, the incident light energy is from the short wavelength side. rays effectively contribute to power generation in a relatively shallow region of the device, and the long wavelength side is absorbed in a shallow region of the device (proceeds to a relatively deep region of the device and effectively contributes to power generation there). By bundling it together, a large photoelectric conversion efficiency can be obtained as a whole of the device.

(f) Effect The photovoltaic device of the present invention is as clear from the explanation in 1- below.
The amorphous silicon-based semiconductor layer used in F4T for power generation has a layer containing nitrogen and boron at the same time, so the spectral sensitivity wavelength of the semiconductor layer can be adjusted without deteriorating the film quality (on the short wavelength side). By making the transition to 11 possible, it is possible to prevent deterioration of photoelectric conversion efficiency due to long-term 1]1 light irradiation,
Photoelectric conversion, which has been the primary goal of research and development up until now, can be made to work from a different perspective.

Furthermore, the semiconductor layer 1 to be rejected is arranged on the light incident side, the semiconductor layer is made a first power generation region, and a second power generation region having a small optical bandgap width is superimposed on this first P power region ( - the tandem structure with a small (dualistic forbidden band width)
If this type of device is applied to an end-layer type with laminated layers, a photoelectric conversion efficiency similar to that of the entire device can be obtained, and the low conversion efficiency can be eliminated. 2C (Calm down, useful, Chiru.

[Brief explanation of the drawing]

Figure 1 shows the nitrogen content of amorphous silicon nitrite! Fe against the spoon! The second reason is the characteristic that shows the movement of the Remi level. 82 lb gas 1. lt '1 ratio (
Figure 4 is a characteristic diagram showing the movement of the Fermi level with respect to B2 and L2.
The change in conductivity with respect to the H6 gas flow ratio (B-containing electric current) is shown in the T characteristic diagram, and the 85 flash shows a one degree change in the current light flux distribution.[Characteristic diagram ,・Figure 6 shows an example of the use of the X invention device (111 direction figure, $7 figure is its spectral sensitivity characteristic diagram,
C shows respectively. ([1...substrate, +31...semiconductor layer. ) October 7, 1982 Solar electromotive force device 6, Person making amendments Patent applicant Address: 2-18 Keihan Hondori, Moriguchi City Name (188) Sanyo Electric Co., Ltd. Representative: Kaoru Iue 4, Agent address: Moriguchi type Keihan Hondori 2nd Ryome 18-5, details to be amended (JF 6, contents of amendment ρi N?' Full text is corrected on the attached sheet).

Claims (1)

[Claims] ([) In a photovoltaic device including an amorphous silicon-based semiconductor layer that contributes to power generation, the semiconductor layer has a layer containing nitrogen and boron at the same time. A photovoltaic device characterized by: