Diamond/β-Ga2O3 pn heterojunction diodes fabricated by low-temperature direct-bonding

Heterojunctions consisting of p-type diamond substrates and thin exfoliated n-type β-Ga2O3 layers were fabricated at a low temperature using a direct-bonding technique. We have fabricated p+-diamond/n-Ga2O3 (p+–n) and p-diamond/n-Ga2O3 (p–n) structures with different B concentrations in diamond. The p+–n heterojunction exhibited Ohmic behavior, resulting from p+-diamond behaving as a metallic layer. As for the p–n heterojunction, it showed clear rectifying action as a conventional bipolar action with a rectifying ratio >108 at ±10 V and leakage current