Reduction of the Optical Losses in CdTe/ZnTe Thin-Film Solar Cells

Abstract

We report on reduction of optical losses in n-CdTe/p-ZnTe thin-lm solar cells grown by molecular beam epitaxy. The investigated thin-lm devices were grown from elemental sources on monocrystalline, semi-insulating, (100)-oriented GaAs substrates. The optical losses have been reduced by a texturing of the device surface and by depositing of a ZnO antireection coating. Currentvoltage and spectral characteristics of the investigated p-ZnTe/n-CdTe solar cells depend signicantly on the preparation of the surface of the ZnTe window. We describe a procedure of chemical etching of the ZnTe window leading to surface texturing. A ZnO layer of proper thickness deposited by low-temperature atomic layer deposition technique on the ZnTe surface forms an eective antireection coating that leads to the reduction of optical losses. Due to reduction of the optical losses we observe increase of the short-circuit current, JSC, by almost 60% and of the energy conversion eciency by 44%.

Quasi Fermi Level Scan of Band Gap Energy in Photojunction

“…Continuously ongoing advanced studies aimed at indepth understanding of the physics of photovoltaic heterojunctions [1][2][3][4][5][6][7][8][9] and improvement of construction of solar cells [10][11][12][13][14][15] and ultraviolet sensitive photodetectors [16][17][18] are in line with the search of renewable energy sources supporting the sustainable civilization development. The comprehensive theory of solar cells exists and can be found in textbooks [3][4][5][6] convenient models describing particular aspects of electricity generation in a solar cell, facilitating experimental data interpretation or useful as an enlightening example are still welcome.…”