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Optical band-gap of InSb0.97Bi0.03 thin films

Research paper by Ketan Chaudhari, P.H. Soni; Ashwini Mahadik

Indexed on: 01 Jun '18Published on: 28 May '18Published in: Vacuum



Abstract

Publication date: August 2018 Source:Vacuum, Volume 154 Author(s): Ketan Chaudhari, P.H. Soni, Ashwini Mahadik Nowadays, there has been extensive interest shown in infrared detectors operating in the 8–12 μm wavelength region wherein minimum atmospheric absorption is present. The more developed III-V materials are preferred to II-VI compounds. InSb, among the III-V semiconductors, has sufficiently narrow band-gap suitable in this regard. InSb crystallizes into the zinc-blende structure. However, the band-gap of InSb is considerably wide for Low Wavelength IR applications. The band-gap can be reduced by incorporation of Bi atoms into host InSb. Thin films of InSb0.97Bi0.03 were grown at room temperature on (001) NaCl crystal substrates under a pressure of 10−5 Pa using the thermal evaporation technique. The films obtained were characterized using FTIR absorption spectra. From the absorption data analysis, the band-gap is determined. It has been observed that Bi doping reduces the band-gap of InSb by a fair degree and, with film thickness the band-gap is found to change too.