β-Ga2O3 is an ultra-wide bandgap semiconductor highly attractive for next-generation high-voltage power electronics, but its device development is hindered by the lack of effective p-type doping. Here, we report a vertical β-Ga2O3 Schottky barrier diode with a p-i-n junction composite termination integrated with a high-resistivity implanted region. A double-layer p-Cr2O3 structure is employed on the mesa sidewall, and ion implantation assisted by the mesa slope is used to form a high-resistivity implanted region to suppress reverse leakage and optimize electric field distribution. The optimized device exhibits a breakdown voltage of 6.6 kV, a specific on-resistance of 4.1 mΩ cm2, and a power figure of merit of 10.69 GW/cm2, together with low turn-on voltage and good stress reliability. This composite termination structure effectively suppresses leakage and enhances voltage capability, providing a promising route for high-performance β-Ga2O3 power devices.
Ion energy control during plasma-enhanced atomic layer deposition (PEALD) allows for tailoring the properties of thin films. The energy of ions impacting the growth surface during plasma exposure can be controlled by applying a substrate bias, generally at a radio frequency (RF) of 13.56 MHz for PEALD. This approach, however, typically results in broad ion flux–energy distribution functions (IFEDFs) and can influence the plasma through changes in plasma density. Tailored waveform (TW) biasing provides an alternative, enabling narrow IFEDFs without affecting the plasma otherwise. In this Letter, TW biasing at 200 kHz was implemented during the PEALD of various metal nitrides, where a range of benefits was observed. TW biasing reduced oxygen incorporation in AlN films. For the conductive nitrides TaCxN1−x, WCxNy, TiN, and NbN, TW biasing led to significant improvements in electrical resistivity, with TaCxN1−x additionally showing enhanced crystallinity. More broadly, TW biasing during PEALD offers the potential for more controlled tuning of material properties compared to conventional RF biasing.
Here, a bias-tunable dual-mode ultraviolet (UV) photodetector based on p-Mg-GaN/β-Ga2O3 heterojunction is reported. The device mainly responds to UVC (254 nm) under reverse bias and actively switches to UVA (365 nm) response under low forward bias. When the forward bias voltage exceeds ∼2 V, a significant negative photoconductivity (NPC) phenomenon occurs. Under 365 nm illumination, the NPC originates from the instantaneous filling of interface states and the barrier modulation at the heterojunction. In contrast, the mechanism under 254 nm illumination exhibits a strong bias dependence: at 4 V, it is governed by a slow process associated with bulk deep-level states; when the bias increases to 6 V, the dominant process changes to rapid interface barrier modulation. This study reveals the bias-tunable NPC mechanism switching phenomenon in Ga2O3 heterojunctions and provides a new physical basis and material platform for the design of intelligent ultraviolet photodetectors with spectral selectivity and adjustable polarity.
Integrating barium titanate (BTO) films on SiO2/Si-based platforms is essential for the development of future nanophotonic modulators in photonic integrated circuits (PIC). However, the integration of BTO films on these amorphous platforms is far from trivial. In this work, the direct growth of tetragonal crystal (p4 mm)-textured BTO films on 4-in. SiO2/Si using a magnesium oxide (MgO) buffer layer by a magnetron sputtering process is developed. This work presents a systematic study on the evolution of crystallographic orientation and anisotropy energy in BTO films as a function of film thickness. Furthermore, a detailed analysis is conducted on the growth kinetics of BTO films, with the thickness-dependent evolution of surface morphology and Ba/Ti. Simultaneously, strain-engineered BTO films with a Curie temperature (Tc > 360 °C) are demonstrated. This integration method overcomes the lattice matching limitation between BTO and the amorphous substrate, offering a low-cost, flexible integration approach for next-generation PIC platforms.
The relentless push for higher power densities and miniaturization in electronics and electrified transportation has placed stringent demands on dielectric materials, which must simultaneously conduct heat and block charge. Yet, these two functions are inherently antagonistic. The biomimetic assembly of nanoscale building blocks offers a promising route to circumvent this trade-off, yet inevitably introduces a high density of heterointerfaces whose charge dynamics remain poorly captured by conventional macroscopic models. Here, we construct highly ordered nacre-mimetic architectures from 1D aramid nanofibers and 2D boron nitride nanosheets, achieving an 80% enhancement in breakdown strength up to 371.56 kV/mm. Thermally stimulated depolarization current analysis reveals a dense population of deep-level traps with a characteristic activation energy of 1.43 eV, while first-principles calculations identify a massive 2.1 eV conduction band offset arising from interfacial charge redistribution. This combination generates a built-in electric field sufficient to impose potent potential barriers that suppress carrier injection, while the deep traps, whose microscopic origin we attribute to the non-ideal 1D/2D interface, are proposed to immobilize hot electrons and truncate avalanche breakdown. Our findings establish a synergistic physical picture where morphological ordering and electronic band engineering collectively overcome the long-standing thermal conductivity–insulation deadlock, offering a viable pathway toward robust dielectrics for next-generation high-power systems.
