Material characteristics of metalorganic chemical vapor deposition of Bi2Te3 films on GaAs substrates

Abstract

Metal organic chemical vapor deposition has been investigated for growth of Bi2Te3 films on (0 0 1) GaAs substrates using trimethylbismuth and diisopropyltelluride as metal organic sources. The results of surface morphology, electrical and thermoelectric properties as a function of growth parameters are given. The surface morphologies of Bi2Te3 films were strongly dependent on the deposition temperatures. Surface morphologies varied from step-flow growth mode to island coalescence structures depending on deposition temperature. In-plane carrier concentration and electrical Hall mobility were highly dependent on precursor's ratio of VI/V and deposition temperature. By optimizing growth parameters, we Could clearly observe an electrically intrinsic region of the carrier concentration at the temperature higher than 240 K. The high Seebeck coefficient (of -160 mu VK-1) and good surface morphology of this material is promising for Bi2Te3-based thermoelectric thin film and two-dimensional supperlattice device applications. (c) 2006 Elsevier B.V. All rights reserved.