Acceptor formation mechanisms determination from electrical and optical properties of p-type ZnO doped with lithium and nitrogen

Abstract

A lithium (Li) and nitrogen (N) dual-doped p-type ZnO film (ZnO : (Li,N)) was deposited on c-plane sapphire by RF-magnetron sputtering of Zn–2 at.% Li alloy using mixed gases of oxygen and nitrogen and then annealing in N2 flow. It has a carrier concentration of 3.07 × 1016 cm−3 and Hall mobility of 1.74 cm2 V−1 s−1. XPS measurement shows that there are LiZn–N complexes in the p-type ZnO : (Li,N), which are demonstrated by photoluminescence measured at various temperatures and different excitation powers to be acceptors and responsible for p-type conductivity of the ZnO : (Li,N). The optical level of the LiZn–N complex acceptor is estimated to be about 126 meV by measurement of emission energy of free electron to the acceptor level.