Effect of Ar+ ion implantation on the properties of electrodeposited cdte thin films

Abstract

Semiconducting nanomaterials of II-VI groups are the key elements of continued technological approaches made in the field of optoelectronic, magnetic and photonic devices due to their size-dependent properties. Ion beams create changes in the material along their track; this not only exhibits excellent properties but also tailors new materials. This article reports the effect of Ar+ ion implantation on the properties of cadmium telluride thin films of about 80 nm thickness. The implantation parameters were adjusted based on computer-aided learning using SRIM (stopping and range of ions in matter) software. The CdTe thin films were deposited by electrodeposition method on ITO substrate. Thin films of CdTe are exposed to Ar+ ions with different fluencies of 1 × 1015, 5 × 1015 and 1 × 1016 ions cm-2 at Ion Beam Centre, Kurukshetra University, Kurukshetra, India. After implantation, the films were characterized using UV-visible spectroscopy, photoluminescence (PL) and a four-probe set-up with a programmable current-voltage (I-V) source metre. The scanning electron microscopy of pristine film showed smooth and uniform growth of sphere-shaped grains on substrate surface. From optical studies, the values of optical band gap for as-deposited and argon-ion-implanted thin films were calculated. It was found that values of optical band gap decreased with the increase in fluence of ion beam. From PL studies it was found that the intensity got increased with ion fluence. A considerable increase in current was noticed from I-V measurements with ion fluence after implantation. Different properties of pre- and post-implanted thin films are studied.