Carrier transport in transparent oxide semiconductor with intrinsic structural randomness probed using single-crystalline InGaO3(ZnO)(5) films

摘要

We have investigated carrier transport in a crystalline oxide semiconductor InGaO3(ZnO)(5) using single-crystalline thin films. When carrier concentration is less than 2x10(18) cm(-3), logarithm of electrical conductivity decreases in proportion to T (-1/4) and room-temperature Hall mobility was as low as similar to1 cm(2)(V s)(-1). When carrier concentration was increased to 4x10(18) cm(-3), the conduction mechanism changed to degenerate conduction and room-temperature Hall mobility was steeply increased to >10 cm(2)(Vs)(-1), showing metal-insulator transition behavior. These results are explained by percolation conduction over distribution of potential barriers formed around conduction band edge. The potential distribution is a consequence of potential modulation originating from random distribution of Ga3+ and Zn2+ ions in the crystal structure of InGaO3(ZnO)(5). (C) 2004 American Institute of Physics.