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【International Papers】Impact of Solid-State Charge Injection on Spectral Photoresponse of NiO/Ga₂O₃ p–n Heterojunction
日期：2024-02-04阅读：170
Researchers from the University of Central Florida have published a dissertation titled " Impact of Solid-State Charge Injection on Spectral Photoresponse of NiO/Ga2O3 p–n Heterojunction " in Condensed Matter.
Abstract
Forward bias hole injection from 10-nm-thick p-type nickel oxide layers into 10-μm-thick n-type gallium oxide in a vertical NiO/Ga2O3 p–n heterojunction leads to enhancement of photoresponse of more than a factor of 2 when measured from this junction. While it takes only 600 s to obtain such a pronounced increase in photoresponse, it persists for hours, indicating the feasibility of photovoltaic device performance control. The effect is ascribed to a charge injection-induced increase in minority carrier (hole) diffusion length (resulting in improved collection of photogenerated non-equilibrium carriers) in n-type β-Ga2O3 epitaxial layers due to trapping of injected charge (holes) on deep meta-stable levels in the material and the subsequent blocking of non-equilibrium carrier recombination through these levels. Suppressed recombination leads to increased non-equilibrium carrier lifetime, in turn determining a longer diffusion length and being the root-cause of the effect of charge injection.
Figure 1. Schematics for the vertical p-n NiO/Ga2O3 heterojunction with the respective majority carrier concentrations and thicknesses. The centripetal arrows on the top plane of Si-doped 10-μm-thick n-type Ga2O3 layer show directions for a lateral diffusion and drift of light-induced non-equilibrium minority holes moving towards the depletion layer, which extends by ~180 nm beyond the p-niO/n-Ga2O3 interface.
Figure 2. (a) Room temperature forward and reverse I-V (Current-Voltage) curves (linear and logarithmic scales) from the NiO/Ga2O3 p–n heterojunction shown in Figure 1. (b) Forward branch of the I–V curve shown in Figure 2 (a linear and logarithmic scale). The value for forward turn-on voltage of ~1.9 V is obtained via the intersection of the dashed black line, tangential to the I–V curve, with the voltage axis.
Paper Link：https://doi.org/10.3390/condmat8040106
