利用分子束外延设备在蓝宝石衬底上生长了B/N共掺的p型ZnO薄膜, 对比了B/N共掺和N单掺杂样品的物理学性能。通过X射线光电子能谱测试证明了在薄膜中存在有B和B—N键。B/N共掺样品的空穴浓度比单一N掺杂样品高近两个量级。且ZnO∶(B,N)薄膜在两年多的时间内一直显示稳定的p型电导。这是由于B—N键的存在提高了N在ZnO薄膜中的固溶度,且B—N键之间强的键能和B占据Zn位所表现的弱施主特性不会带来强的施主补偿效应, 说明B是N掺杂ZnO薄膜的一种良好的共掺元素。

A stable and repeatable p-type ZnO is the key to realize the practical applications of photoelectric devices. Nitrogen has been considered as a possible acceptor dopant for p-type ZnO for a long time. However, the low solubility of nitrogen acceptor at oxygen site in ZnO is considered to be one of the main obstacles for p-type ZnO. In this paper, B/N co-doped p-type ZnO thin films were grown on sapphire substrate by plasma-assisted molecular beam epitaxy. The effect of boron on the nitrogen doping was studied by comparing with the single nitrogen doped thin films. X-ray photoelectron spectroscopy demonstrated there exists boron and B—N bond in the ZnO thin film. Compared to the single N-doped sample, B/N codoped samples present much higher carrier density. And the ZnO∶(B,N) thin films show stable p-type conduction in two years. It is attributed to the increase of solubility of nitrogen acceptor. It benefits from the strong B-N bonding and weak donor character of boron at zinc site. Boron will not bring strong compensation for acceptors. It suggests that boron is a good co-doping candidate for nitrogen doped ZnO thin films.