Growth and characterization of CdZnS thin film buffer layers by chemical bath deposition
In this paper we report the study of CdZnS thin films grown on the soda-lime glass (SLG) substrates by chemical bath deposition (CBD) process for buffer layer applications in CuGaSe/sub 2/ (CGS) solar cells. Structural, surface morphology, optical, and electrical properties of as-deposited CdZnS films were investigated by XRD, SEM, spectrophotometer, and four probes resistivity measurements as a function of Zn-composition in the solution. The CdZnS films have hexagonal structures. The grain size of CdZnS films was found to increase with increasing Zn-content in the solution. The films with 30% of Zn in the solution showed a better than 80% transmittance for wavelengths longer than 600 nm and film thickness less than 50 nm. The values of energy band gaps obtained are 2.40, 2.55, and 2.70 eV for Zn-content of 0, 30, and 50%, respectively. The resistivity of CdZnS films was found to increase as the Zn content increases.
Low‐resistivity ZnCdS films for use as windows in heterojunction solar cells
Low‐resistivity ZnxCd1−xS films have been obtained by a multisource evaporation method. The films have been doped with In during the deposition. The resistivity of such films varies from 2×10−3 Ω cm for x=0 up to 2 Ω cm for x=0.3 and rises up to 1012 Ω cm for x=1. For energies lower than the energy gap, the transparency of these films, when corrected for the reflection loss, can reach a value of almost 100%. In the range of an x variation between 0 and 0.4 these films, because of their low resistivity and their high transparency, can be used as windows in heterojunction solar cells.
Electrical transport behaviour of CdS/CuGaSe2 thin film heterojunction
Abstract n-CdS/p-CuGaSe 2 thin film heterojunctions have been prepared by laser evaporating CuGaSe 2 onto vacuum evaporated CdS films. The dark current-voltage characteristics have been measured at different temperatures. They show that current transport is dominated by tunneling mechanism below room temperature while recombination of charge carriers is observed for temperatures above 303 K. The C-V measurements are also studied and the results are discussed.