ON THE VARIABLE HOPPING RANGE CONDUCTIVITY IN ZnO DOPED SYSTEMS
TITUS SANDU 1, RODICA PLUGARU 1, NECULAI PLUGARU 2 1. National Institute for R & D in Microtechnologies (IMT), Erou Iancu Nicolae Str. 126A, Bucharest 077190, P.O. BOX 38-160, Romania
2. National Institute of Materials Physics, Atomistilor Str. 105bis, Magurele-Bucharest 077125, P.O. Box MG-07, Ilfov, Romania
At low temperatures materials like semiconductors with impurities and/or defects show a Variable Range Hopping (VRH) conduction mechanism. This mechanism is important in wide-bandgap semiconductors which are technologically relevant in transparent electronics. In this paper we analyze the VRH conduction mechanism in Al doped ZnO. Our study is based on ab-initio electronic structure calculations. A careful analysis of the effect of carrier concentration illustrates that for a doping below 2 % the VRH mechanism is dominant in Al doped ZnO. Our results are in agreement with experimental data on growth and characterization of Al doped ZnO films.
