Optimization of synthesis conditions of thin Te-doped InSb films and first principles studies of their physicochemical properties

Highlights: • Composition of In-Sb-Te films can be tuned by electrodeposition conditions. • Te precursor concentration affects the morphology and roughness of deposited films. • InSb and Sb₂Te₃ phases are formed during co-electrodeposition of In, Sb and Te. • Dopant content influences the optical band gap of Te-doped InSb. The main objective of our study was to develop an electrochemical synthesis method for obtaining Te-doped InSb thin films. The electrodeposition was performed using a pulse mode in a citrate bath containing 0.06 M InCl₃, 0.045 M SbCl₃ and 0–0.008 M TeO₂. Firstly, the optimization of following parameters was carried out: the potential of pulse "off" (E_off), duration of pulse "off" (t_off), and the ratio of time "on" to time "off" (t_on/t_off). We have confirmed that appropriate selection of electrodeposition conditions allows obtaining a material with a controllable morphology and chemical composition. Based on performed studies, optimal parameters for electrodeposition of thin Te-doped InSb films were selected. In the next stage, the pulse electrodeposition of Te-doped InSb films at previously optimized conditions was conducted from a solution containing different concentrations of the TeO₂ precursor. It was demonstrated that adjustment of the TeO₂ content in the citrate bath allows controlling the dopant concentration in thin Te-doped InSb films. Such a controllable synthesis creates the opportunity for tuning physicochemical properties of the material. The effect of doping on the crystal structure, phase composition, surface roughness, and optical band gap of thin Te-doped InSb films was discussed in detail.