Electric Properties of AlGaN/GaN/Si High Electron Mobility Transistors

This work investigated the electrical properties in AlGaN/GaN/Si HEMTsgrown by molecular beam epitaxy. The electrical behavior have been investigated using by electric permittivity, modulus formalism and conductance measurements. As has been found from electrical conductance, dispersive behavior is related to barrier inhomogeneity and deep trap in barrier layer. On the other hand, the strain relaxation of charge transport is studied both permittivity and electric modulus formalisms.

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

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

Multiple machine learning approach to characterize two-dimensional nanoelectronic devices via featurization of charge fluctuation

Two-dimensional (2D) layered materials such as graphene, molybdenum disulfide (MoS2), tungsten disulfide (WSe2), and black phosphorus (BP) provide unique opportunities to identify the origin of current fluctuation, mainly arising from their large surface areas compared with those of their bulk counterparts. Among numerous material characterization techniques, nondestructive low-frequency (LF) noise measurement has received significant attention as an ideal tool to identify a dominant scattering origin such as imperfect crystallinity, phonon vibration, interlayer resistance, the Schottky barrier inhomogeneity, and traps and/or defects inside the materials and dielectrics. Despite the benefits of LF noise analysis, however, the large amount of time-resolved current data and the subsequent data fitting process required generally cause difficulty in interpreting LF noise data, thereby limiting its availability and feasibility, particularly for 2D layered van der Waals hetero-structures. Here, we present several model algorithms, which enables the classification of important device information such as the type of channel materials, gate dielectrics, contact metals, and the presence of chemical and electron beam doping using more than 100 LF noise data sets under 32 conditions. Furthermore, we provide insights about the device performance by quantifying the interface trap density and Coulomb scattering parameters. Consequently, the pre-processed 2D array of Mel-frequency cepstral coefficients, converted from the LF noise data of devices undergoing the test, leads to superior efficiency and accuracy compared with that of previous approaches.