Room temperature electrodeposition of aluminum antimonide compound semiconductor

AlSb is a group III–V compound semiconductor material that is conventionally grown by high temperature processes such as Czochralski and Bridgman methods. Development of a method to synthesize AlSb at room temperature will be more economical to help modulate the electronic properties. In this investigation, a pulsed potential electrodeposition method using a room temperature molten salt system (aluminum trichloride, AlCl3/1-methyl-3-ethylimidazolium chloride, EMIC) with an addition of SbCl3 is discussed. The potential pulse parameters were established by carrying out cyclic voltammetry at different concentrations of SbCl3 and with varying molar ratios of AlCl3/EMIC. Stoichiometric AlSb deposits were obtained from an acidic AlCl3/EMIC (1.5:1 molar ratio) melt containing 4 × 10−3 mol/l of SbCl3 onto an ordered TiO2 nanotubular template. The AlSb compound was predominantly amorphous in as-deposited condition and annealing at 350 °C for 2 h in argon transformed into crystalline phase. The AlSb deposit showed a high resistivity in the order of 109 Ω-cm and a defect concentration of 1016 cm−3 which was attributed to presence of carbon. The deposits obtained from a basic melt (0.67:1 molar ratio of AlCl3/EMIC) were enriched with antimony.