Solar cell

• US 8,404,513 B2
• Filed: 06/01/2012
• Issued: 03/26/2013
• Est. Priority Date: 04/27/2011
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsushita, Akio, Itoh, Akihiro, Nakagawa, Tohru, Ishida, Hidetoshi
• Primary Examiner(s): Nikmanesh, Seahvosh
• Assistant Examiner(s): Seven, Evren
• Application Number:
  US13/486,843
• Publication Number:
  US 20120301993A1
• Time in Patent Office: 298 Days
• Field of Search: None
• US Class Current: 438/93
• CPC Class Codes: H01L 31/0543 comprising light concentrating means of the refractive type, e.g. lenses
• CPC Class Codes: H01L 31/0687 Multiple junction or tandem solar cells
• CPC Class Codes: H01L 31/0693 the devices including, apart from doping material or other impurities, only AIIIBV compounds, e.g. GaAs or InP solar cells
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

A method for generating electric power including the steps of: (a) preparing a solar cell having a condensing lens and a solar cell element, wherein the solar cell element includes an n-type GaAs layer, a p-type GaAs layer, a quantum tunneling layer, an n-type InGaP layer, a p-type InGaP layer, a p-type window layer, an n-side electrode, and a p-side electrode, and satisfies the following equation (I): d2<d1, d3<d1, nanometer≦d2≦4 nanometers, 1 nanometer≦d3≦4 nanometers, d5<d4, d6<d4, 1 nanometer≦d5≦5 nanometers, 1 nanometer≦d6≦5 nanometers, 100 nanometers≦w2, 100 nanometers≦w3, 100 nanometers≦w4, and 100 nanometers≦w5. . . (I); and (b) irradiating a region S which is included in the surface of the p-type window layer through the condensing lens with light to satisfy the following equation (II) in order to generate a potential difference between the n-side electrode and the p-side electrode: w6≦w1. . . (II).

Claims

1. A method for generating electric power with use of a solar cell, the method comprising steps of:

(a) preparing the solar cell comprising a condensing lens and a solar cell element, wherein

the solar cell element comprises an n-type GaAs layer, a p-type GaAs layer, a quantum tunneling layer, an n-type InGaP layer, a p-type InGaP layer, a p-type window layer, an n-side electrode, and a p-side electrode;

a Z-direction denotes the direction of the normal line of the p-type GaAs layer;

an X-direction denotes a direction orthogonal to the Z-direction,

the n-type GaAs layer, the p-type GaAs layer, the quantum tunneling layer, the n-type InGaP layer, the p-type InGaP layer, and the p-type window layer are stacked along the Z-direction in this order;

the p-type window layer is made of a p-type compound semiconductor having a wider bandgap than InGaP,

the n-side electrode is electrically connected with the n-type GaAs layer;

the p-side electrode is electrically connected with the p-type InGaP layer;

the n-type GaAs layer is divided into a GaAs center part, a first GaAs peripheral part, and a second GaAs peripheral part;

the GaAs center part is interposed between the first GaAs peripheral part and the second GaAs peripheral part along the X-direction;

the first GaAs peripheral part and the second GaAs peripheral part have a shape of a layer,

the n-type InGaP layer is divided into an InGaP center part, a first InGaP peripheral part, and a second InGaP peripheral part;

the InGaP center part is interposed between the first InGaP peripheral part and the second InGaP peripheral part along the X-direction;

the first InGaP peripheral part and the second InGaP peripheral part have a shape of a layer,

the following inequation set (I) is satisfied;

d2<

d1, d3<

d1, 1 nanometer≦

d2≦

4 nanometers, 1 nanometer≦

d3≦

4 nanometers, d5<

d4, d6<

d4, 1 nanometer≦

d5≦

5 nanometers, 1 nanometer≦

d6≦

5 nanometers, 100 nanometers≦

w2, 100 nanometers≦

w3, 100 nanometers≦

w4, and 100 nanometers≦

w5 

 

(I);

wherein d1 represents a thickness of the GaAs center part along the Z-direction;

d2 represents a thickness of the first GaAs peripheral part along the Z-direction;

d3 represents a thickness of the second GaAs peripheral part along the Z-direction;

d4 represents a thickness of the InGaP center part along the Z-direction;

d5 represents a thickness of the first InGaP peripheral part along the Z-direction;

d6 represents a thickness of the second InGaP peripheral part along the Z-direction;

w2 represents a width of the first GaAs peripheral part along the X-direction;

w3 represents a width of the second GaAs peripheral part along the X-direction;

w4 represents a width of the first InGaP peripheral part along the X-direction; and

w5 represents a width of the second InGaP peripheral part along the X-direction; and

(b) irradiating a region S which is included in the surface of the p-type window layer through the condensing lens with light in such a manner that the following inequation (II) is satisfied so as to generate a potential difference between the n-side electrode and the p-side electrode;

w6≦

w1 

 

(II);

wherein w1 represents a width of the GaAs center part along the X-direction;

w6 represents a width of the region S along the X-direction in the cross-sectional view which includes the Z-direction; and

the first GaAs center part overlaps the region (S) when seen from the Z-direction.

2. The method according to claim 1, wherein

the width of the n-type InGaP layer is equal to the width of the p-type window layer.

3. The method according to claim 1, wherein

the solar cell element further comprises an n-type barrier layer interposed between the n-side electrode and the GaAs center part.

4. The method according to claim 1, wherein

the solar cell element further comprises an n-type contact layer interposed between the n-side electrode and the GaAs center part.

5. The method according to claim 1, wherein

the solar cell element further comprises a p-type contact layer interposed between the p-side electrode and the p-type InGaP layer.

6. The method according to claim 1, wherein

the solar cell element further comprises an n-type barrier layer interposed between the quantum tunneling layer and the InGaP center part.

7. The method according to claim 1, wherein

the solar cell element further comprises a p-type barrier layer interposed between the p-type GaAs layer and the quantum tunneling layer.

8. The method according to claim 1, wherein

the sides of the n-type GaAs layer, the p-type GaAs layer, the quantum tunneling layer, the n-type InGaP layer, the p-type InGaP layer, and the p-type window layer are covered by an insulating film.