发表机构
The Ohio State University; Case Western Reserve University（俄亥俄州立大学; 凯斯西储大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过对比mist-CVD生长的导电与绝缘LiGa5O8薄膜，发现缺锂及β-Ga2O3次生相形成是p型导电的关键，提出界面电荷转移机制。
AI 中文摘要
LiGa5O8是一种超宽禁带氧化物半导体，最近已被实验证明具有p型导电性；然而，所观察到的p型输运的起源仍知之甚少。在这项工作中，我们通过系统比较在不同生长条件下通过雾化学气相沉积（mist-CVD）生长的、表现出p型导电性或绝缘行为的LiGa5O8薄膜的电学、成分和结构性质，来研究p型导电性的起源。p型导电薄膜在室温下的空穴浓度约为10^18 cm^-3。研究发现，p型导电性的出现与薄膜的元素组成密切相关，X射线光电子能谱（XPS）显示，p型导电薄膜中Li/Ga比降低，表明其成分缺锂。拉曼光谱和X射线衍射（XRD）进一步揭示，p型导电薄膜中存在β-Ga2O3的特征，而这些特征在绝缘薄膜中不存在，证明形成了二次β-Ga2O3相。考虑到LiGa5O8与β-Ga2O3之间已报道的II型能带对齐，以及理论上预测的与Li空位（V_Li）相关的受主能级，提出混合LiGa5O8/β-Ga2O3相的形成可促进电子从β-Ga2O3价带转移到LiGa5O8中的受主态，从而促进空穴积累和p型导电性。
英文摘要
LiGa5O8 is an ultrawide-bandgap oxide semiconductor that has recently been experimentally demonstrated to exhibit p-type conductivity; however, the origin of the observed p-type transport remains poorly understood. In this work, we investigate the origin of p-type conductivity by systematically comparing the electrical, compositional, and structural properties of mist chemical vapor deposition (mist-CVD) grown LiGa5O8 thin films exhibiting either p-type conductivity or insulating behavior under different growth conditions. The p-conductive films exhibit room-temperature hole concentrations on the order of 10^18 cm^-3. The emergence of p-type conductivity is found to be strongly correlated with the elemental composition of the films, with X-ray photoelectron spectroscopy (XPS) revealing a reduced Li/Ga ratio in the p-conductive films, indicative of a Li-deficient composition. Raman spectroscopy and X-ray diffraction (XRD) further reveal signatures of \b{eta}-Ga2O3 in the p-conductive films that are absent in the insulating films, demonstrating the formation of a secondary \b{eta}-Ga2O3 phase. Considering the reported type-II band alignment between LiGa5O8 and \b{eta}-Ga2O3, together with theoretically predicted acceptor levels associated Li vacancies (V_Li) in LiGa5O8, the formation of mixed LiGa5O8/\b{eta}-Ga2O3 phases is proposed to facilitate electron transfer from the \b{eta}-Ga2O3 valence band to acceptor states in LiGa5O8, thereby promoting hole accumulation and p-type conductivity.
Comments22 pages, 7 figures
