Electrodeposition of p-Type Sb₂Te₃ Films and Micro-Pillar Arrays in a Multi-Channel Glass Template

Antimony telluride (Sb₂Te₃)-based two-dimensional films and micro-pillar arrays are fabricated by electrochemical deposition from electrolytes containing SbO⁺ and HTeO₂⁺ on Si wafer-based Pt electrode and multi-channel glass templates, respectively. The results indicate that the addition of tartaric acid increases the solubility of SbO⁺ in acidic solution. The compositions of deposits depend on the electrolyte concentration, and the micro morphologies rely on the reduction potential. Regarding the electrolyte containing 8 mM of SbO⁺ and 12 mM of HTeO₂⁺, the grain size increases and the density of films decreases as the deposition potential shifts from -100 mV to -400 mV. Sb₂Te₃ film with nominal composition and dense morphology can be obtained by using a deposition potential of -300 mV. However, this condition is not suitable for the deposition of Sb₂Te₃ micro-pillar arrays on the multi-channel glass templates because of its drastic concentration polarization. Nevertheless, it is found that the pulsed voltage deposition is an effective way to solve this problem. A deposition potential of -280 mV and a dissolve potential of 500 mV were selected, and the deposition of micro-pillars in a large aspect ratio and at high density can be realized. The deposition technology can be further applied in the fabrication of micro-TEGs with large output voltage and power.