Investigation of Cu-doping effects in CdTe solar cells by junction photoluminescence with various excitation wavelengths

Abstract

Cu-doping effects and a CdSxTe1−x mixed crystal layer in CdS/CdTe solar cells were investigated on the basis of the photoluminescence (PL) of the CdS/CdTe junction using excitation lights incident on the glass substrate side (junction PL) with various excitation wavelengths. In the Cu-doped CdS/CdTe solar cells, broad emissions at 910–950 nm, which were probably caused by donor–acceptor pair (DAP) emission between CuCd acceptors and ClTe donors, were observed. The intensity of the junction PL markedly increased owing to the Cu doping. This result suggests that the intensity of junction PL is relevant to the conversion efficiency of CdTe solar cells. Furthermore, the PL peak energy increased with increasing excitation wavelength. This result indicates that the CdSxTe1−x mixed crystal layer is formed in the CdS/CdTe interface, and that the S composition decreased from the CdS/CdTe interface to the rear.

Effects of Cu doping on CdTe thin-film solar cells in substrate configuration

“…10) In the conventional superstrate configuration, a CdS x Te 1-x mixed crystal layer is formed in the CdS/CdTe interface due to the intermixing of CdS and CdTe. [16][17][18][19][20][21][22][23][24][25][26] The formation of the CdS x Te 1-x mixed crystal layer is very important for reducing the interface states at the CdS/CdTe interface, because there is a large lattice mismatch between CdTe and CdS. [16][17][18][19][20][21][22][23][24][25][26] However, it is difficult to form the CdS x Te 1-x mixed crystal layer in substrate configuration, because the deposition temperature of the CdS layer is lower than that of the CdTe layer.…”

Gamma-ray irradiation effects on CdTe solar cell dosimeter

“…The CdTe solar cells were fabricated by the method reported in previous papers. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] For evaluation of the γ-ray tolerance, γ-ray irradiation was divided into multiple time-frames. γ irradiations were provided at the 60 Co γ-ray irradiation facility at Institute for Integrated Radiation and Nuclear Science, Kyoto University.…”

Formation and characterization of ZnS and CdZnS films using open-air chemical vapor deposition for buffer layers of compound semiconductor solar cells

“…Cadmium sulfide (CdS) has been used as a buffer layer in various types of solar cells, including CuIn x Ga 1−x Se 2 (CIGS), CdTe, Cu 2 ZnSnS 4 (CZTS), and Cu 2 SnS 3 (CTS) solar cells. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] However, there are some issues with the CdS buffer layer. The first issue is that the buffer layer absorbs incident light in the short wavelength region (less than 512 nm) due to the relatively narrow bandgap of CdS (E g = 2.42 eV).…”

“…This method has been used previously to form CdS buffer layers for CdTe solar cells. 6,[8][9][10][11][12] In this method, a ZnS or CdZnS film is created from gas sublimated from solid gas source. Since the forming process of the ZnS or CdZnS film does not involve water, this method avoids the problem caused by the difference in solubility between ZnS and CdS.…”