Temperature-dependent device properties of γ-CuI and β-Ga2O3 heterojunctions

Abstract

Temperature-dependent studies of Ga2O3-based heterojunction devices are important in understanding its carrier transport mechanism, junction barrier potential, and stability at higher temperatures. In this study, we investigated the temperature-dependent device characteristics of the p-type γ-copper iodide (γ-CuI)/n-type β-gallium oxide (β‐Ga2O3) heterojunctions, thereby revealing their interface properties. The fabricated γ-CuI/β-Ga2O3 heterojunction showed excellent diode characteristics with a high rectification ratio and low reverse saturation current at 298 K in the presence of a large barrier height (0.632 eV). The temperature-dependent device characteristics were studied in the temperature range 273–473 K to investigate the heterojunction interface. With an increase in temperature, a gradual decrease in the ideality factor and an increase in the barrier height were observed, indicating barrier inhomogeneity at the heterojunction interface. Furthermore, the current–voltage measurement showed electrical hysteresis for the reverse saturation current, although it was not observed for the forward bias current. The presence of electrical hysteresis for the reverse saturation current and of the barrier inhomogeneity in the temperature-dependent characteristics indicates the presence of some level of interface states for the γ-CuI/β‐Ga2O3 heterojunction device. Thus, our study showed that the electrical hysteresis can be correlated with temperature-dependent electrical characteristics of the β‐Ga2O3-based heterojunction device, which signifies the presence of surface defects and interface states. Article Highlights We revealed the interface properties of p-type γ-copper iodide (γ-CuI) and n-type β-gallium oxide (β-Ga2O3) heterojunction. The developed heterostructure showed a large barrier height (0.632 eV) at the interface, which is stable at a temperature as high as 473 K. We confirmed the current transport mechanism at the interface of the heterojunction by analyzing the temperature dependent current–voltage characterization. Graphic abstract

Characteristics of Vertical Ga2O3 Schottky Junctions with the Interfacial Hexagonal Boron Nitride Film

“…The mid- and high-frequency Raman peaks are at around 354, 424, 486, 640, and 657 cm –1 , corresponding to distortion of Ga 2 O 6 octahedra and the stretching/bending of the GaO 4 tetrahedra, respectively, as also discussed in previous reports. 41 , 42 These analyses show a successful transfer of the CVD-synthesized hBN film on the bulk β-Ga 2 O 3 substrate. The hBN/β-Ga 2 O 3 sample was further studied by X-ray photoelectron spectroscopy (XPS) analysis.…”

“…The XRD spectra are shown in the JCPD card number 06-0246. 41 Figure 2 c shows a scanning electron microscopy (SEM) image for the transferred hBN layer on the β-Ga 2 O 3 substrate.…”

“…A strong diffraction peak at 61.01 cm –1 corresponding to the (020) reflection phase of β-Ga 2 O 3 was observed for the sample. The XRD spectra are shown in the JCPD card number 06-0246 Figure c shows a scanning electron microscopy (SEM) image for the transferred hBN layer on the β-Ga 2 O 3 substrate.…”

“…Previously, we have demonstrated the integration of highly conducting graphene and copper iodide (γ-CuI) films with the β-Ga 2 O 3 substrate for the fabrication of deep-UV photoresponsive devices. 41 , 42 The fabrication of quasi-two-dimensional metal–insulator–semiconductor field-effect transistors was demonstrated by the mechanical transfer process of hBN and nanothin flakes of β-Ga 2 O 3 . 43 In contrast to previous reports, we show how to make a vertical Ni/β-Ga 2 O 3 Schottky junction with and without the hBN interfacial layer.…”

Temperature-Dependent Self-Powered Solar-Blind Photodetector Based on Ag2O/β-Ga2O3 Heterojunction

“…Figure 7 E shows a logarithmic plot of the J–V characteristics with small electrical hysteresis at the reverse saturation current according to the post-annealing temperature. The presence of electrical hysteresis in the reverse saturation current exhibits the quality of interface states and surface defects for the Ag 2 O/β-Ga 2 O 3 heterojunction [ 54 , 55 ]. It was confirmed that the difference in reverse current and the reverse saturation current decreased as the post-annealing temperature increased, showing the narrowest gap at 300 °C.…”