Photoelectric conversion element, photoelectric conversion system, and method for production of photoelectric conversion element

Abstract

A photoelectric conversion element of an embodiment is a photoelectric conversion element which performs photoelectric conversion by receiving illumination light having n light emission peaks having a peak energy Ap (eV) (where 1≦p≦n and 2≦n) of 1.59≦Ap≦3.26 and a full width at half maximum Fp (eV) (where 1≦p≦n and 2≦n), wherein the photoelectric conversion element includes m photoelectric conversion layers having a band gap energy Bq (eV) (where 1≦q≦m and 2≦m≦n), and the m photoelectric conversion layers each satisfy the relationship of Ap−Fp<Bq≦Ap with respect to any one of the n light emission peaks.

What is claimed is:  
     
         1 . A photoelectric conversion system comprising:
 an illuminator having n (n is a natural number) light emission peaks each having a peak energy Ap (eV) (where 1≦p≦n and 2≦n) of 1.59≦Ap≦3.26 and a full width at half maximum Fp (eV) (where 1≦p≦n and 2≦n); and   an electronic device having a photoelectric conversion element, the element includes m photoelectric conversion layers having a band gap energy Bq (eV) (where 1≦q≦m and 2≦m≦n), and the m (m is a natural number) photoelectric conversion layers each satisfy the relationship of Ap=Fp<Bq≦Ap with respect to any one of the n light emission peaks.   
     
     
         2 . The system according to  claim 1 , wherein m=n. 
     
     
         3 . The system according to  claim 1 , wherein the m photoelectric conversion layers each satisfy the relationship of Ap−0.9 Fp<Bq<Ap−0.7 Fp with respect to any one of the n light emission peaks. 
     
     
         4 . The system according to  claim 1 , wherein the m photoelectric conversion layers have a composition denoted as In x Ga y Al z N (0<x≦1, 0≦y<1, 0≦z<1 and x+y+z≦1). 
     
     
         5 . The system according to  claim 1 , wherein the electronic device is a portable information terminal. 
     
     
         6 . A method for manufacturing a photoelectric conversion element comprising:
 forming a GaN-based n-type semiconductor layer on a substrate;   forming on the n-type semiconductor layer a first photoelectric conversion layer having a composition denoted as In x1 Ga y1 Al z1 N (0<x1≦1, 0≦y1<1, 0≦z1<1 and x1+y1+z1≦1);   forming on the first photoelectric conversion layer a second photoelectric conversion layer having a composition denoted as In x2 Ga y2 Al z2 N (0<x2≦1, 0≦y2<1, 0≦z2<1 and x2+y2+z2≦1) wherein x1<x2;   forming a GaN-based p-type semiconductor layer on the second photoelectric conversion layer;   forming a p-side electrode on the p-type semiconductor layer;   removing the substrate to expose the n-type semiconductor layer; and   forming an n-side electrode on the n-type semiconductor layer on a side opposite to the first photoelectric conversion layer.   
     
     
         7 . The method according to  claim 6 , wherein a heat dissipation layer of copper (Cu) is formed on the p-side electrode. 
     
     
         8 . The method according to  claim 6 , wherein a reflection layer of silver (Ag) is formed between the p-type semiconductor layer and the p-side electrode. 
     
     
         9 . The method according to  claim 6 , wherein the n-type semiconductor layer, the first photoelectric conversion layer, the second photoelectric conversion layer and the p-type semiconductor layer are formed by a MOCVD method. 
     
     
         10 . A method for manufacturing a photoelectric conversion element comprising:
 forming a GaN-based first p-type semiconductor layer on a substrate;   forming on the first p-type semiconductor layer a first photoelectric conversion layer having a composition denoted as In x1 Ga y1 Al z1 N (0<x1≦1, 0≦y1<1, 0≦z1<1 and x1+y1+z1≦1);   forming on the first photoelectric conversion layer a second photoelectric conversion layer having a composition denoted as In x2 Ga y2 Al z2 N (0<x2≦1, 0≦y2<1, 0≦z2<1 and x2+y2+z2≦1) wherein x1<x2;   forming a GaN-based n-type semiconductor layer on the second photoelectric conversion layer;   forming an n-side electrode on the n-type semiconductor layer;   removing the substrate to expose the first p-type semiconductor layer;   forming a second p-type semiconductor layer on the first p-type semiconductor layer on a side opposite to the first photoelectric conversion layer; and   forming a p-side electrode on the second p-type semiconductor layer on a side opposite to the first photoelectric conversion layer.   
     
     
         11 . A method for manufacturing a photoelectric conversion element comprising:
 forming a GaN-based p-type semiconductor layer on a substrate;   forming on the p-type semiconductor layer a first photoelectric conversion layer having a composition denoted as In x1 Ga y1 Al z1 N (0<x1≦1, 0≦y1<1, 0≦z1<1 and x1+y1+z1≦1);   forming on the first photoelectric conversion layer a second photoelectric conversion layer having a composition denoted as In x2 Ga y2 Al z2 N (0<x2≦1, 0≦y2<1, 0≦z2<1 and x2+y2+z2≦1) wherein x1<x2;   forming a GaN-based n-type semiconductor layer on the second photoelectric conversion layer;   forming an n-side electrode on the n-type semiconductor layer;   removing the substrate to expose the p-type semiconductor layer; and   forming a p-side electrode of ITO or ZnO on the p-type semiconductor layer on a side opposite to the first photoelectric conversion layer.   
     
     
         12 . The method according to  claim 11 , wherein the ITO or ZnO is deposited by a sputtering method.