ON THE VARIABLE HOPPING RANGE CONDUCTIVITY IN ZnO DOPED SYSTEMS

  • TITUS SANDU
    National Institute for R & D in Microtechnologies (IMT), Erou Iancu Nicolae Str. 126A, Bucharest 077190, P.O. BOX 38-160, Romania
  • RODICA PLUGARU
    National Institute for R & D in Microtechnologies (IMT), Erou Iancu Nicolae Str. 126A, Bucharest 077190, P.O. BOX 38-160, Romania
  • NECULAI PLUGARU
    National Institute of Materials Physics, Atomistilor Str. 105bis, Magurele-Bucharest 077125, P.O. Box MG-07, Ilfov, Romania

Abstract

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.

Cuvinte cheie

Variable Range Hopping transparent semiconductors Coherent Potential Approximation Density Functional Theory