材料科学および工学ジャーナル

Low-temperature Heat Treatment (80°C) Effect on the Electrochemically Synthesized CuInTe2 Thin Films for Energy Harvesting Applications

Abstract

Lakhe M and Chaure NB

We have investigated the effect of low-temperature (80ºC) post-deposition heat treatment onto CuInTe2 (CIT) thin films prepared by one-step electrochemical technique. Aqueous precursor solution consisting ionic species of Cu, In and Te with pH 4.0 was used for the growth of CIT layers. The deposition potential was optimized using cyclic voltammetry. Conventional three-electrode geometry was used to electrodeposit CIT thin films onto CdS substrates. The structural, optical, morphological, compositional and transport properties were studied with the aid of XRD, Raman, HRTEM, UV-Visible, FESEM, EDAX, I-V and C-V measurements. As-deposited samples were amorphous in nature, however upon heat treatment highly crystalline CIT thin films with tetragonal crystal structure were exhibited. The values of energy band gap for the films deposited at -0.7 V and -0.8 V versus Ag/AgCl were estimated to be in the range 1.02 eV to 1.1 eV. Compact, uniform, void free and well adherent films were deposited at -0.7 V and -0.8 V. The samples were heat treated at 80ºC for 60 minutes therefore, visible changes in the surface morphology were not observed by SEM. Indium rich films were electrodeposited for -0.7 V and -0.8 V, however upon heat treatment stoichiometric layers were obtained. Schottky diodes are formed with Au metal contact in all cases. The solar cell investigated under illumination at 1.5 AM exhibits the short circuit current density (Jsc), 40.75 mA/cm2; open circuit voltage (Voc), 255 mV; fill factor (FF), 41% and power conversion efficiency (η), 4.01%. This low-temperature heat treatment procedure could be advantageous for the fabrication of CIT solar cells onto flexible substrates.