FORMATION OF CONDUCTIVE CdO THIN FILMS ON PHOTOCONDUCTIVE CdS THIN FILMS FOR WINDOW LAYER APPLICATIONS IN SOLAR CELLS

Abstract

We report the formation of a thin layer of CdO on chemically deposited CdS thin films during air anneal at 370°C to 500°C for 5 min to 120 min. During a 5 min anneal, the sheet resistance of the CdS thin films drops from about 1013 □/9 to 3.5 k□/□(370°C) and 470 □/□(500°C). X-ray diffraction studies showed that this is associated with the formation of a thin layer of CdO layer, which occurs at temperatures above 370°C. The CdS, which remains under the conductive CdO top layer, is photosensitive - with photo-to-dark current ratio of 103 - 104. Essentially the air annealing converts the highly resistive and highly photosensitive intrinsic (i) CdS thin film into a (i)CdS-( n +)CdO layer. The technique offers prospects to convert the top part of a chemically deposited CdS thin film window layer of high photosensitivity, deposited on an absorber layer, to a conductive layer. This is of interest in thin film solar cell technology.

Influence of hydrogenation on the electrical and optical properties of CdO thin films

“…Degenerate semiconducting cadmium oxide CdO material attracts a great attention due to its electrical and optical properties. Films prepared from pure and metal-doped CdO have been widely studied for extensive optoelectronic applications in transparent conducting oxides (TCO), solar cells, smart windows, optical communications, flat panel displays, photo-transistors, as well as other types of applications like IR heat mirror, gas sensors, low-emissive windows, thin-film resistors, etc [1][2][3][4][5].…”

Drastic improvement in magnetization of CdO nanoparticles by Fe doping

“…Furthermore, CdO nanoparticles have interesting properties such as low electrical resistivity in the range of * 10 -2 -10 -4 X cm and high transmission in the visible region (Waghulade et al 2007; Lewis and Paine 2000;Yan et al 2001;Carballeda-Galicia et al 2000). CdO and TM-doped CdO are valuable for a wide range of optoelectronic applications such as transparent conducting oxide, photo transistors, photo diodes, solar cells, transparent electrodes, and gas sensors (Aydn et al 2012;Zhao et al 2002;Daza et al 2001). Hence, TM ions such as Mn, Co, Ni, Cu, and Fe have been tried as dopants for CdO, with the objective of modify some of their properties (Jin et al 2001;Ahmad et al 2013Ahmad et al , 2014Dakhel 2014).…”

Physical Properties of Cdo Thin Films Prepared by Spray Pyrolysis Technique

“…hin film technologies play the pivotal role specifically in the field of microelectronics, optical coating, integrated optics and superconductors etc [1].Cadmium oxide (CdO) have face center cubic(FCC)structure with directBand-gap between(2.3 and 2.5) eV is an n-type semiconductor and one of the promising transparent conducting oxides (TCO) with high electrical conductivityand optical transmittance in visible spectralregion [2].Which has foundextensive applications in solar cells [3], low emissive window optical communications, flat panel display, photo-transistors, photodiodes, transparent electrodes and gas sensors [4][5][6][7][8].Varioustechniques have been employed to prepare CdO thin films such as chemical vapor deposition [6], spray pyrolysis [2], solution growth [9], SILAR Deposition Technique [7], pulsed laser deposition [5] and sol-gel method [4].The chemical technique of spray pyrolysiswhich is simple to handle economically viable is used for several decades in glass [10].In the present work, optical and electrical properties have been performed for analysis of the deposited CdO thin films on glass and silicon wafer substrates was studied.…”