Carbon-Nanotube/β-Ga₂O₃ Heterojunction PIN Diodes

β-Ga2O3 is gaining attention as a promising semiconductor for next-generation high-power, high-efficiency, and high-temperature electronic devices, thanks to its exceptional material properties. However, challenges such as the lack of viable p-type doping have hindered its full potential, particularly in the development of ambipolar devices. This work introduces a heterojunction diode (HD) that combines p-type carbon nanotubes (CNTs) with i- and n-type β-Ga2O3 to overcome these limitations. For the first time, a CNT/β-Ga2O3 hetero-p-n-junction diode is fabricated. Compared to a traditional Schottky barrier diode (SBD) with the same β-Ga2O3 epilayer, the CNT/β-Ga2O3 HD demonstrates significant improvements, including a higher rectifying ratio (1.2 × 1011 ), a larger turn-on voltage (1.96 V), a drastically reduced leakage current at temperatures up to 300 °C, and a 26.7% increase in breakdown voltage. Notably, the CNT/β-Ga2O3 HD exhibits a low ideality factor of 1.02, signifying an ideal interface between the materials. These results underline the potential of CNT/β-Ga2O3 heterojunctions for electronic applications, offering a promising solution to the current limitations in β-Ga2O3-based devices.