Ultrawide bandgap LiGa5O8/β-Ga2O3 heterojunction p–n diodes

Ultrawide bandgap (UWBG) semiconductor β-phase Ga2O3 has attracted significant interest for potential power electronics applications. This, however, is hindered by the lack of effective p-type dopants in β-Ga2O3. A p–n heterojunction utilizing the recently discovered UWBG p-type LiGa5O8 in conjunction with n-type (010) β-Ga2O3 is demonstrated in this work. Ohmic contacts to the UWBG p-type material, LiGa5O8, were achieved via a combinational Pt/Ni/Au metal stack. Obvious improvement in contact resistance was observed with annealing of the contact metal at 375 °C for 1 min in N2 ambient. Rectifying characteristics with a turn-on voltage of 5.46 V and an ideality factor of 2.78 were extracted from the p-LiGa5O8/n-Ga2O3 heterojunction. Current density change of more than 7 orders of magnitude was obtained between the off-state and on-state of the diodes measured. This work provides a potential pathway to fully utilize the high breakdown field associated with β-Ga2O3 for high power device applications with a p-type material that has an even wider bandgap (and therefore a potentially higher breakdown field) than β-Ga2O3.