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Identifying defects/traps is of vital importance for the implementation of high-performance Ga2O3 power devices. In this work, majority and minority carrier traps in beta-gallium oxide ($\beta $ -Ga2O3) have been investigated and identified by means of deep level transient spectroscopy (DLTS) in Ni/ $\beta $ -Ga2O3 Schottky barrier diode (SBD) and NiO/ $\beta $ -Ga2O3 p+-n heterojunction diode (HJD). For both diodes, a dominant energy level of majority carrier (electron) trap states is determined to be ${E}_{C}-$ (0.75–0.79) eV with a concentration of (2.4–4.1) $\times 10^{{13}}$ cm $^{-{3}}$. Meanwhile, an additional trapping level at ${E}_{V} +0.14$ eV with a concentration of 1.2 $\times 10^{{14}}$ cm $^{-{3}}$ yield is present in NiO/ $\beta $ -Ga2O3 bipolar HJD but absent in the Ni/ $\beta $ -Ga2O3 SBD unipolar counterpart. The detection of such minority carrier traps originates from the hole injection through trap-assisted tunneling (TAT) from $\text{p}^{+}$ -NiO to $\beta $ -Ga2O3. The bias- and frequency-dependent DLTS characteristics identify that such shallow-level minority carrier traps are located in the $\beta $ -Ga2O3 bulk region rather not interfacial states at the NiO/ $\beta $ -Ga2O3 heterointerface. The identification of both majority and minority carrier traps in this work may shed light on the in-depth understanding of carrier transport mechanisms in Ga2O3-based unipolar and bipolar power devices. [ABSTRACT FROM AUTHOR]

Resonant antennas have garnered considerable interest in terahertz and visible regimes owing to its extraordinary localized field concentration capability. In this work, we experimentally demonstrate a novel metal-free terahertz detector, which is fashioned by heavily doped polysilicon using standard CMOS process. The computational results show that the incident field can be largely enhanced within the antenna gap area at the resonance of 650 GHz. The room temperature measured results show that the responsivity and noise equivalence power of the detector integrated with the optimized antenna design is 600 V/W and 200 pW/Hz0.5 at 650 GHz, respectively. Aided by an equivalent circuit model, theoretical analysis is carried out to elucidate that the field enhancement ratio of the resonant polysilicon antenna is comparable to gold made antenna at terahertz frequencies. Our study provides a new approach for designing a low-cost and CMOS-compatible terahertz detector characterized with strongly localized field, projecting more insights on light-matter interaction at terahertz frequencies. [ABSTRACT FROM AUTHOR]

More and more attention has been paid to the heterogeneous semiconductor device based on the wafer-bonding method due to its high-quality wafer-bonded active layer. In this paper, we first theoretically study the dependence of the single-photon properties, including the single-photon detection efficiency (SPDE), dark count rate (DCR), and afterpulsing probability (AP), of the wafer-bonded Ge/Si single-photon avalanche photodiode (SPAD) on the interface state at the Ge/Si (hydrophilic reaction) and Si-Si (hydrophobic reaction or surface-activated method) wafer-bonded interface based on the Poisson statistics. It is found that the interface state density and the energy level position of the interface state significantly affect the linear-mode electric field distribution (avalanche probability), 3-dB bandwidth (dark carriers), gain (quantum efficiency), and effective transit time (trapped carriers), which in turn affect the DCR and the SPDE. Furthermore, the dependence of the AP on the avalanche charge and the interface recombination rate is clarified as well. It is expected that this paper may give guidance for the fabrication of high-performance SPAD. [ABSTRACT FROM PUBLISHER]

Electron-leakage is a deep-rooted problem for nitride-based light-emitting diodes (LEDs), particularly for AlGaN-based deep-ultraviolet (DUV) LEDs. In this paper, a specific design for the electron-blocking structure in AlGaN DUV LEDs, increasing the Al composition of the last quantum barrier to the same value as that of the electron-blocking layer accompanied with composition-graded p-AlGaN layer, is proposed to reduce electron leakage. Simulation results demonstrate that this design can effectively reduce electron leakage and hence increase internal quantum efficiency. Furthermore, fabricated devices with at an emitting wavelength of 292 nm verify remarkably enhanced light-output power. At 20-mA injection current, the proposed structure achieved a light-output increment as high as 98%, compared with the conventional structure. [ABSTRACT FROM PUBLISHER]