Rectifying the Current−Voltage Characteristics of a LiNbO₃ Film/GaN Heterojunction

Epitaxial LiNbO₃ (LNO) films are grown on n−type GaN semiconductor substrates, forming LNO/GaN p-n junctions. The current-voltage (I–V) and capacitance−voltage (C–V) characteristics of the junctions are studied. The I–V curve shows a clear rectifying property with a turn−on voltage of 2.4 V. For the forward voltages, the conduction mechanism transits from Schottky thermionic emission for low voltages to space-charge-limited current for large voltages. Reverse C–V characteristics exhibit a linear 1/C² versus V plot, from which a built-in potential of 0.34 V is deduced. These results are explained using the energy-band structure of the LNO/GaN junction.