Spray pyrolysis deposition of p-CdTe films: Structural, optical and electrical properties

Abstract

The present communication reports the structural, optical and electrical properties of p-CdTe films deposited by using spray pyrolysis technique on thoroughly cleaned sodalime glass substrates at 350°C in inert N2 atmosphere. The films were characterized by using XRD, Raman spectroscopy, XPS, thickness profiler, SEM, EDAX and UV–Visible spectroscopy and Hall parameters measurement. The structural studies showed the formation of pure cubic CdTe in resultant films with crystallite size=32nm. The texture coefficient TC(hkl) indicated preferential orientation of films along [311] and [511] directions. The SEM image showed almost spherical granules with average size of 0.25μm. From UV–Visible spectral data, the maximum absorbance and direct band gap obtained using Tauc plot are found to be 0.94 and Eg=1.44eV respectively for films having thickness, t=3.2μm. The Hot probe experiment, Hall coefficient RH=1.478×103cm3/C, and resistivity ρ=2.228×101Ωcm confirmed the p-type semiconducting behavior of CdTe films. The mobility of majority charge carriers – holes is found to be μ=6.63×101cm2/Vs. The films processed using present work can be treated as possible p-type candidate for fabrication of hetero-junction solar cell.