Interface Doping Mechanism of p-Type Conductivity in Mist-CVD-Grown LiGa5O8 Thin Films
Abstract
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.
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BibTeX
@misc{yu2026interface,
title = {{Interface Doping Mechanism of p-Type Conductivity in Mist-CVD-Grown LiGa5O8 Thin Films}},
author = {Dong Su Yu and Shashu Tomar and Zixiu Huang and Kaitian Zhang and Sarker Md. Sadman and Vijay Gopal Thirupakuzi Vangipuram and Ye Lin and Walter R. L. Lambrecht and Roberto C. Myers and Hongping Zhao},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10401},
eprint = {2610.10401},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10401},
}
RIS
TY - UNPB
TI - Interface Doping Mechanism of p-Type Conductivity in Mist-CVD-Grown LiGa5O8 Thin Films
AU - Dong Su Yu
AU - Shashu Tomar
AU - Zixiu Huang
AU - Kaitian Zhang
AU - Sarker Md. Sadman
AU - Vijay Gopal Thirupakuzi Vangipuram
AU - Ye Lin
AU - Walter R. L. Lambrecht
AU - Roberto C. Myers
AU - Hongping Zhao
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10401
UR - https://arxiv.org/abs/2610.10401
AB - 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.
ER -