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

• Spray pyrolysis deposition is simple route for film deposition.
• Spray pyrolysis processing at 350 °C gives phase pure, p-type CdTe films.
• CdTe films deposited at 350 °C have uniform spherical particle size distribution.
• CdTe needs inert atmosphere for crystallization.
• Minor oxidization at CdTe surface is due to molecular atmospheric oxygen.

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 = 32 nm. The texture coefficient TC(h k l) indicated preferential orientation of films along [3 1 1] and [5 1 1] directions. The SEM image showed almost spherical granules with average size of 0.25 μm. From UV–Visible spectral data, the maximum absorbance and direct band gap obtained using Tauc plot are found to be 0.94 and Eg = 1.44 eV respectively for films having thickness, t = 3.2 μm. The Hot probe experiment, Hall coefficient RH = 1.478 × 103 cm3/C, and resistivity ρ = 2.228 × 101 Ω cm confirmed the p-type semiconducting behavior of CdTe films. The mobility of majority charge carriers – holes is found to be μ = 6.63 × 101 cm2/Vs. The films processed using present work can be treated as possible p-type candidate for fabrication of hetero-junction solar cell.