n-HgxCd₁₋xSe thin film electrodes for photoelectrochemical applications

Abstract

Mercury cadmium selenide (HgxCd₁₋xSe) thin film semiconductor photoelectrodes of various compositions (0 ≤ x ≤ 0.2) are fabricated on glass and stainless steel substrates by a simple chemical bath technique. The different preparation parameters and deposition conditions are optimized to yield quality samples. By increasing the Hg-content in host CdSe- lattice, an optical gap (Eg) of the alloyed semiconductor is reduced from 1.72 to 1.06 eV, which corresponds to maximum absorption in the visible and near infra-red regions of solar spectrum. The photoelectrochemical (PEC) cells are then fabricated and studied for their performance through the various parameters. It has been observed that the flat band potential (Vfb) increased with electrode composition, x and reached a maximum at x = 0.01. The variations in the photopotential (Vph) and photocurrent (Iph) are studied as a function of the electrode composition. Both Vph and Iph are found to be boosted significantly and are explained on the basis of the electrode materials properties.