Fabrication and study of bulk and thin film CuGa1-xIn xSe2 and Cu(Ga1-xIn)3Se5 photovoltaic materials obtained by the close-spaced vapour transport technique (CSVT)

In this paper we present a preparation of new bulk and thin film photovoltaic materials, CuGa_1-xIn_xSe₂ and Cu(Ga_1-xIn_x)₃Se₅, for fabrication of solar cells. The bulk materials are synthesised by the Bridgman technique. The elements Cu, Ga, In, and Se are placed in suitable proportions in a sealed vacuum flask under a vacuum of 10^-6 torr. This flask undergoes slow thermal treatment upto a temperature just above the synthesis melting temperature ≅1100°C and then is cooled to the ambient temperature. We have realised thin films by the close-spaced vapour transport (CSVT) technique in a closed tube, iodine acts as the transport agent. The bulk and thin film samples are characterised by X-ray diffraction and energy dispersive spectrometry. The CSVT technique is very simple and low cost and permits good quality crystalline samples to be obtained with the aim of realising solar cells used in the conversion of solar energy