Majority and Minority Carrier Traps in NiO/β-Ga₂O₃ p⁺-n Heterojunction Diode

Ga2O3 Bipolar Heterojunction-Based Optoelectronic Synapse Array with Visual Attention

“…I−V characterization under a high sweep voltage (from 4.0 to determined by Hall measurements. As investigated previously, the overall built-in voltage (V bi ) between the Ga 2 O 3 and NiO heterostructure is 2.5 V, 34 and thus, V p-bi at the Li:NiO side is calculated to be 0.07 V, while V n-bi in the Si:Ga 2 O 3 side is 2.43 V. It suggests that the flat band is achieved across the heterojunction as the forward bias increases to 2.5 V. When the forward voltage increases to 5.0 V, the energy band in the Ga 2 O 3 side bends downward with a potential of 2.43 eV, as shown in Figure 2f. Consequently, when the forward voltage increases, oxygen vacancies with the possible deep energy levels of 1.38 or 1.76 eV 35 are quickly filled with injected electrons.…”

“…Specifically, the ratio of built-in fields on the n side ( V n‑bi ) and p side ( V p‑bi ) is V n‑bi / V p‑bi = ε Ga 2 O 3 n Ga 2 O 3 /ε NiO p NiO = 0.03, in which the dielectric constants of both Si:Ga 2 O 3 (ε Ga 2 O 3 ) and Li:NiO (ε NiO ) are approximately 10 and the electron concentration in Si:Ga 2 O 3 ( n Ga 2 O 3 ) and the hole concentration in Li:NiO ( p NiO ) are 3 × 10 17 and 1 × 10 19 cm –2 , respectively, determined by Hall measurements. As investigated previously, the overall built-in voltage ( V bi ) between the Ga 2 O 3 and NiO heterostructure is 2.5 V, and thus, V p‑bi at the Li:NiO side is calculated to be 0.07 V, while V n‑bi in the Si:Ga 2 O 3 side is 2.43 V. It suggests that the flat band is achieved across the heterojunction as the forward bias increases to 2.5 V. When the forward voltage increases to 5.0 V, the energy band in the Ga 2 O 3 side bends downward with a potential of 2.43 eV, as shown in Figure f. Consequently, when the forward voltage increases, oxygen vacancies with the possible deep energy levels of 1.38 or 1.76 eV are quickly filled with injected electrons.…”

Superior high temperature performance of 8 kV NiO/Ga2O3vertical heterojunction rectifiers

“…The forward current transport mechanism in such junctions is typically recombination at low biases and trap-assisted tunneling at higher bias. 10,21–26 Promising rectifier performance has been reported with this approach, 14–36 including V B of 8.32 kV, with figure of merit 13.2 GW cm −2 . 15…”

15 MeV proton damage in NiO/β-Ga2O3vertical rectifiers

“…This has led to recent demonstrations of vertical rectifiers with breakdown voltages more than 8 kV with excellent high temperature operation [9]. While the device performance is promising in terms of dc and switching applications [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], little is known about the effects of radiation on these heterojunctions. While the Ga 2 O 3 is known to be relatively resistant to total dose damage [27,28], large reversible changes in current-voltage characteristics of the heterojunctions have been observed after Co-60 gamma ray exposure which appears to be due to conductivity changes in the NiO [29].…”