Nitrogen and copper doping in MgxZn1-xO films and their impact on p-type conductivity

Abstract

We report on nitrogen (N) and copper (Cu) doping in MgxZn 1-xO films grown via remote-plasma-enhanced metalorganic chemical vapor deposition and their impact on p-type conduction. The Mg xZn1-xO films showed a transformation of conductivity from n-type to p-type with increasing Mg content (x), which occurred at x=0.078 with N2 carrier gas and x=0.106 with H2 carrier gas. A comparison of the temperature dependent photoluminescence and the Hall effect measurement data revealed that the transformation of the conduction type with the increasing Mg content of MgxZn1-xO films is due to a conduction band up shift that causes the enhancement of the activation energy of donor states and the reduction of n-type residual electron concentrations. The p-type conductivity of MgxZn1-xO films with a low value of Mg content with N2 carrier gas was due to the contribution from the (N)O acceptor. Though N doped MgxZn1-xO (MgxZn1-xO:N) films showed p-type conductivity for x >0.078, the N and Cu co-doped MgxZn1-xO (Mg xZn1-xO:Cu,N) films showed n-type conduction with larger electron concentrations. Despite being a good acceptor, Cu doped Mg xZn1-xO films had an n-type conductivity that was due to the contribution from shallow donors such as Cui and Cu sZni. Moreover, the reduction of the Mg content of Mg xZn1-xO:Cu,N films led to an increase in the residual electron concentrations and contributed to the n-type conductivity. © 2011 American Institute of Physics.