Anisotropic electrical properties of NiO x /β-Ga2O3 p-n heterojunctions on (201), (001), and (010) crystal orientations

Abstract NiO x / β -Ga 2 O 3 p-n heterojunctions fabricated on ( 2 ̅ 01 ) , ( 001 ) , and ( 010 ) β -Ga 2 O 3 substrates show distinctly anisotropic electrical properties. All three devices exhibited excellent rectification ≥10 9 , and turn-on voltages >2.0 V. The ( 010 ) device showed very different turn-on voltage, specific on-resistance, and reverse recovery time compared with ( 2 ̅ 01 ) and ( 001 ) devices. Moreover, it is calculated that the interface trap state densities for ( 2 ̅ 01 ) , ( 001 ) , and ( 010 ) plane devices are 4.3 × 10 10 , 7.4 × 10 10 , and 1.6 × 10 11 eV –1 cm –2 , respectively. These differences in the NiO x / β -Ga 2 O 3 heterojunctions are attributed to the different atomic configurations, the density of dangling bonds, and interface trap state densities.