Origins of shallow level and hole mobility in codoped p-type ZnO thin films

Abstract

A combination study of structural, optical, and electrical properties has been carried out on N–In codoped p-type ZnO thin films for the origins of shallow level and hole mobility. The observed small activation energy of ∼20meV for the hole concentration corresponds well to the results from photoluminescence and conductivity data, revealing the grain boundary trapping nature of the shallow level. The achieved hole mobility is mainly due to the lack of grain boundary barrier effect, and the codoping yielded weak ionized impurity scattering. The authors have also revealed the scattering and conduction mechanisms in these p-ZnO films.