Electrodeposition and Characterization of p-type Sb-x Te-y Thermoelectric Thin Films

The electro-deposition of compound semiconductors has been attracting more attention because of its ability to rapidly deposit nanostructured materials and thin films with controlled morphology, dimensions, and crystallinity in a cost-effective manner (1). In particular, low band-gap A(2)B(3)- type chalcogenides, such as Sb2Te3 and Bi2Te3, have been extensively studied because of their potential applications in thermoelectric power generator and cooler and phase change memory. Thermoelectric SbxTey films were potentiostatically electrodeposited in aqueous nitric acid electrolyte solutions containing different ratios of TeO2 to Sb2O3. The stoichiometric SbxTey films were obtained at an applied voltage of -0.15V vs. SCE using a solution consisting of 2.4 mM TeO2, 0.8 mM Sb2O3, 33 mM tartaric acid, and 1M HNO3. The stoichiometric SbxTey films had the rhombohedral structure with a preferred orientation along the [015] direction. The films featured hole concentration and mobility of 5.8 x 10(18)/cm(3) and 54.8 cm(2)/V .s, respectively. More negative applied potential yielded more Sb content in the deposited SbxTey films. In addition, the hole concentration and mobility decreased with more negative deposition potential and finally showed insulating property, possibly due to more defect formation. The Seebeck coefficient of as- deposited Sb2Te3 thin film deposited at - 0.15V vs. SCE at room temperature was approximately 118 mu V/K at room temperature, which is similar to bulk counterparts.