Enhanced optoelectronic and photoelectrochemical characteristics of nebulised spray pyrolysed ‘Cu‿rich CuInS₂ thin film

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• 作者：Jayaraj Tamil Illakkiya ; Parthasarathy Usha Rajalakshmi ; Rachel Oommen ; ^{rachel12in@yahoo.co.in" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Cu-CuInS2 ; Nebulised spray pyrolysis ; structural ; optoelectronic ; Photoelectrochemical
• 刊名：Materials Science in Semiconductor Processing
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：49
• 期：Complete
• 页码：84-91
• 全文大小：1423 K

文摘

CuInS₂ thin films are deposited by nebulised spray pyrolysis technique using the aqueous solutions of CuCl₂, InCl₃ and thiourea on a pre-heated glass substrate with different chemical compositions. The as-deposited films are vacuum annealed at 200 °C. In all cases, thin films are found to be crystallised in chalcopyrite phase with a preferential orientation along (112) direction. The crystalline quality of the films is further enhanced by heat treatment under vacuum. Cu rich CuInS₂ film exhibited better crystallinity and high conductivity compared to CuInS₂ and In rich CuInS₂ thin films. The films exhibited net-like surface structure. The elemental composition of CuInS₂ thin films is controlled by varying Cu/In ratios in precursor. Absorption co-efficient of the films is of the order of 10⁴ cm⁻¹ in the visible region and the films exhibited a band gap of 1.39–1.47 eV. Photoluminescence intensity of all the stoichiometric composition is drastically decreased upon vacuum annealing. This feature may be attributed to the vacation of carriers from shallow traps, thereby increasing the number of surface state densities. The solution resistance and charge transfer resistance of Cu rich CuInS₂ electrode in dark and under light illumination are determined from electrochemical impedance spectroscopy and are found to be 10.22 Ω, 11.36 Ω and 471.6 Ω, 81.97 Ω respectively. The flat band potential and acceptor density of Cu rich CuInS₂ electrode are determined from Mott-Schottky plot and are found to be 0.53 V and 9.25×10²¹ cm⁻³ respectively.