講演情報
[19a-A302-1]Electrical properties of single-crystal p-Cu2O/n-Ga2O3 heterojunction diodes
〇Yun Jia1, Sora Sato1, Aboulaye Traore1, Muhammad Monirul Islam1, Hironori Okumura1, Takeaki Sakurai1 (1.Univ. of Tsukuba)
キーワード：
Ultra Wide bandgap semiconductor、Ga2O3、Cu2O
β-Ga2O3 is a promising power semiconductor material with a cost advantage and high breakdown field. Unipolar devices have made progress. However, the lack of p-type doping capability hinders bipolar device implementation. One solution is exploring p-type materials for heterojunction structures, such as p-type Cu2O.1 Obtaining single-crystal Cu2O thin films remains a challenge. Meanwhile, understanding charge transport mechanisms is crucial for enhancing device performance.In this work, Cu2O films were fabricated through radio frequency sputtering at room temperature (RT) and 600 ℃. Subsequently, Cu2O/β-Ga2O3 heterojunction diodes were constructed using these films. The examination of variations between the built-in potential and turn-on voltage exposed a range of carrier transport mechanisms in the fabricated devices. By numerically fitting the forward J-V characteristics, it was possible to distinguish different carrier transport mechanisms that dominated at varying forward bias voltages. Fig.1(a) and Fig. 1(b) display the fitting results of forward J-V characteristics measured at 300 K for Sample 1 (RT) and Sample 2 (600 ℃), respectively. The relatively high barrier height and the presence of defects in β-Ga2O3 and Cu2O lead to the dominance of trap-assisted tunneling (TAT) in the carrier transport mechanism.2 However, for Sample 1 (RT), at low bias voltages, the carrier transport mechanism is primarily governed by interface recombination because of the high density of interface defects resulting from the polycrystalline nature of films formed at room temperature and the significant lattice mismatch in the heterojunction. This study aids in optimizing Cu2O thin film formation conditions and enhances our understanding of carrier transport mechanisms in β-Ga2O3-based heterojunctions.