Improvement of β-Ga₂O₃-based Schottky barrier UV photodetector by 4H-SiC substrate, intrinsic buffer layer, and graphene surface contact

This work presents a study of a β-Ga₂O₃-based Schottky barrier UV photodetector (SB UV-PD) with careful concern for material properties, device structure, and optimization techniques. The initial is IZTO/β-Ga₂O₃/ITO was calibrated with experimental measurement. The optimization process lies in these three points: using Silicon Carbide (4H-SiC) as substrate, employing a 4H-SiC intrinsic buffer layer, between Ga₂O₃:Si and the 4H-SiC substrate, and using of graphene instead of IZTO as top Schottky contact. The analysis is based on the current density–voltage (J– \(V\) $V$ ) characteristics, responsivity, internal quantum efficiency ( \(IQE\) $\mathit{IQE}$ ), and time-dependent photo-response ( \(T-D PhR\) $T-DPhR$ ). The optimization process was carried out by fine-tuning various parameters like traps in the 4H-SiC, the 4H-SiC buffer layer electronic affinity, and the top contact graphene work function. The best obtained parameters of photocurrent density, responsivity, \(IQE\) $\mathit{IQE}$ , and detectivity are 7.38 × 10^–5 A/cm², 0.074 A/W, 0.57, 5 × 10¹² Jones at − 1 V under 255 nm, respectively.