Charge carrier scattering channels in graphite bridging its valence and conduction band offer an efficient Auger recombination dynamic to promote low energy charge carriers to higher energy states. It is of importance to answer the question whether a large number of charge carriers can be promoted to higher energy states to enhance the quantum efficiency of photodetectors. Here, we present an experimental demonstration of an effective Auger recombination process in the photo-excited nano-graphite film. The time-resolved hot carrier thermalization was analyzed based on the energy dissipation via the Auger scattering channels. We split the Auger recombination occurrence centered at 0.40 eV energy state into scattering and recombination parts, for characterizing the scattering rate in the conduction band and the recombination rate toward the valence band. The scattering time with respect to the energy state was extracted as 8 ps · eV⁻¹, while the recombination time with respect to the energy state was extracted as 24 ps · eV⁻¹. Our study indicates a 300 fs delay between the hot carrier recombination and generation, leading to a 10⁵ ps⁻¹ · cm⁻³ Auger scattering efficiency. The observed duration for the Auger recombination to generate hot carriers is prolonged for 1 ps, due to the hot carriers energy relaxation bottleneck with optical-phonons in the nano-graphite. The presented analytic expression gives valuable insights into the Auger recombination dynamic to estimate its most efficient energy regime for mid-infrared photodetection.

A comprehensive quantum transport study of ultrathin-body silicon double-gate pMOSFETs with gate length Lg= 14, 10, and 7 nm is performed by in-house developed nonequilibrium Green's function solver employing the six-band k · p Hamiltonian. The effects of channel length, body thickness, as well as confinement and transport crystal orientations are studied systematically. Both I-V and C-V characteristics are analyzed in this paper. Furthermore, the CMOS performance benchmarking results, such as switching delay, energy consumption, and their product, are calculated with the influence of parasitic resistances and capacitances treated in an appropriate way. It is found that the crystal orientation effect on drive current is significant at both long and short channel lengths, while its effect on effective capacitance is more observable at Lg = 7 nm. The drive current at Lg = 14 nm and Lg = 7 nm can be well explained by average ballistic hole velocity and source-to-drain tunneling ratio, respectively. Meanwhile, the effective capacitance is not only determined by the density of states but also affected by the distribution of holes in the confined direction. Both intrinsic and extrinsic performance assessments suggest that (001)/[100] and (110)/[001] are the optimal confinement/transport crystal orientation configurations at Lg= 7 nm, while (110)/[110] and (110)/[111] are the best choices at longer gate lengths. As Lg shrinks, both intrinsic and extrinsic performances will be better at a scaled body thickness.

The resistive random access memory with a graphene electrode (GE) is carefully modeled and simulated by considering its geometrical and physical properties. Since the graphene oxide is generated through the migration of oxygen ions from metal oxide to GE affecting current transport in the memory cell, the model of its electrical conductivity with different oxidation degrees is developed, in which the conductivity is exponentially dependent on the oxidation degree. The simulated I-V characteristics, which agree well with those of the experiment, are obtained by selfconsistently solving the current transport, heat conduction, and oxygen vacancy migration equations. Based on the simulation, oxygen vacancy density, temperature distribution, and resistances of high- and low-resistance states are extracted and compared. A low-temperature increase due to low power consumption indicates its great potential for high-density integration.

The low-field hole mobility in p-type inversion-mode silicon (Si) and germanium (Ge) nanosheet (NS) transistors is rigorously calculated by a physics-based theoretical model, where momentum scatterings from phonons, charged impurities, and surface roughness are all considered. With a holistic physical picture of carrier scattering mechanisms, the effects of material, crystal orientation, channel width, strain/stress, and temperature are investigated comprehensively by the in-house developed numerical simulator. This sound and prospective theoretical work paves the way for clarifying the physics of achieving high hole mobility in ultrascaled NS channels, presenting some valuable insights and guidelines about the device design and fabrication for the next-generation CMOS technology.

The performance of optoelectronic devices is affected by various noise sources. A notable factor is the 4.2% lattice mismatch at the Ge/Si interface, which significantly influences the efficiency of Ge-on-Si photodetectors. These noise sources can be analyzed by examining the impact of the Ge/Si interface and deep traps on dark and photocurrents. This study evaluates the impact of these charge traps on key photodetector performance metrics, including responsivity, photo-to-dark current ratio, noise equivalent power (NEP), and specific detectivity (D^*). The trapping effects on charge transport under both forward and reverse bias conditions are monitored through hysteresis analysis. When illuminated with an unmodulated 1550 nm laser, all the key performance metrics exhibit maximum variations at a specific reverse bias. This critical bias marks the transition from saturated to exponential charge transport regimes, where intensified electric fields enhance trap-assisted recombination and thus maximize metric fluctuations.

The device reliability problems of the bonding wire array in gallium nitride (GaN)-based high electron mobility transistor (HEMT) power amplifier become more and more serious due to high-voltage operation, impedance mismatching conditions, and so on. In this paper, both the experimental and theoretical studies on the electrothermal responses of bonding wire arrays in GaN power amplifier are performed. By using the finite element method to self-consistently solve the current transport and heat conduction equations, the temperature distributions of the GaN die surface and the bonding wire array under the continuous wave input signals of different power can be obtained, which are consistent with the experimental results captured by the IR microscopy of the measurement system.