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.