采用射频等离子体辅助分子束外延方法,以N2作为掺杂源,以O2作为辅助分解的气体和氧源,通过等离子体光谱的实时监测来控制掺杂源中各组分的含量,制备了P型ZnO薄膜及同质p—n结。I-V曲线显示该p-n结具有整流特性,直流驱动下获得了稳定的室温电致发光,包括位于420nm附近的发光峰和500-700nm的发光带。
p-type ZnO has attracted more and more attention because it is necessary to fabricate ZnO devices based on current injection. More and more improvements on p-type ZnO and p-n junctions are reported. However, electroluminescence in these works was rarely observed. We have already succeed in fabricating a ZnO p-n junction LED on sapphire substrate by using activated NO plasma. Here, N2 was used as the acceptor dopant and O2 was used as assistant gas as well as oxygen source. Emission spectra of the N2-O2 plasma were monitored in situ to adjust parameters timely. Electronics measurements of the as-grown p-type ZnO on sapphire shows a carrier concentration of 1.2 × 10^18 cm^ -3 and mobility approach to 1 cm^2 · V ^-1 · s^-1 The LED based on p-n junction shows a certain rectification effect and the turn on voltage is 3.10 V, which is consistent with the bandgap of ZnO. Electroluminescence spectra shows two bands: one is at 420 nm, from donoracceptor pairs; and the other ranges from 500 to 700 nm, which is attributed to the emissions from point defects in ZnO.