Plasma-enhanced atomic layer deposition was employed to grow aluminum nitride (AlN) thin films on Si (100), Si (111), and c-plane sapphire substrates at 250 °C. Trimethylaluminum and Ar/N₂/H₂ plasma were utilized as Al and N precursors, respectively. The properties of AlN thin films grown on various substrates were comparatively analyzed. The investigation revealed that the as-grown AlN thin films exhibit a hexagonal wurtzite structure with preferred c-axis orientation and were polycrystalline, regardless of the substrates. The sharp AlN/substrate interfaces of the as-grown AlN are indicated by the clearly resolved Kiessig fringes measured through X-ray reflectivity. The surface morphology analysis indicated that the AlN grown on sapphire displays the largest crystal grain size and surface roughness value. Additionally, AlN/Si (100) shows the highest refractive index at a wavelength of 532 nm. Compared to AlN/sapphire, AlN/Si has a lower wavelength with an extinction coefficient of zero, indicating that AlN/Si has higher transmittance in the visible range. Overall, the study offers valuable insights into the properties of AlN thin films and their potential applications in optoelectronic devices, and provides a new technical idea for realizing high-quality AlN thin films with sharp AlN/substrate interfaces and smooth surfaces.

The development of effective, feasible, stable, and inexpensive electrocatalysts has been a great challenge in the field of overall water splitting (WS). Herein, a bifunctional electrocatalyst (BF ECS), FeCo₂S₄ nanowire (FCS NWs/Ni)/nickel (Ni) foam, with superior HER/OER activity and stability was designed and fabricated using a hydrothermal method. In addition, this efficient method can be used for the synthesis of other bimetallic MCo₂S₄ sulfides (M = Cu, Zn, Mn, etc.). Electrochemical experiments showed the as-synthesized FCS NWs/Ni exhibited overpotentials of 350.5, 203.7, 115.97, and 62.6 mV (0.05, 0.1, 0.2, and 1 M KOH) at the current density of −10 mA cm⁻² for HER, including small overpotentials of 1.51, 1.36, 1.24, and 1.11 V (10 mA cm⁻²) in a 0.05, 0.1, 0.2, and 1 M KOH solution for OER. The FCS NWs/Ni has a splendid electrocatalytic performance which is related to the synergistic effect of cobalt, iron, and sulfur. Specifically, it has excellent electrical conductivity, a higher specific capacity, and a rich redox state of iron, cobalt, and sulfur elements. The results demonstrate a promising method for the design and fabrication of metal BF ECS for overall water splitting.

Polycrystalline hexagonal GaN films were deposited directly on amorphous quartz (fused glass) substrates at 250 °C by plasma-enhanced atomic layer deposition. An atomically sharp GaN/quartz interface is observed from transmission electron microscopy images, which is further demonstrated by x-ray reflectivity measurements. The atomic force microscopy image reveals a smooth surface of GaN. The concentrations of oxygen and carbon impurities in GaN are 6.3 and 0.64%, respectively, according to x-ray photoelectron spectroscopy analysis. The electron mobility measured by Hall is 1.33 cm2 V−1 s−1. The results show that high-quality GaN films are obtained on amorphous quartz substrates, and GaN/quartz can be used as a template for the fabrication of GaN-based devices.

High-quality gallium nitride (GaN) was grown on multilayer graphene via plasma-enhanced atomic layer deposition (PEALD) with a 30 cycles ALD aluminum oxide (Al2O3) Layer as protective barrier. It was found that the Al2O3 layer can effectively protect the graphene from Ar/N2/H2 plasma gas which was used to grow the PEALD GaN. The thickness of the Al₂O₃ interlayer was measured to be ~5 nm through transmission electron microscopy. The properties of the PEALD-deposited GaN have been systematically studied. The results show that the as-deposited GaN is polycrystalline with a preferential (002) growth direction and has a smooth surface. In addition, The atomic percentage of oxygen within the GaN is13.58 at.%. These results prove that high-quality GaN has been grown on ultrathin Al2O3/multilayer graphene. This study presents a viable approach for integrating graphene with GaN devices.

Group III-nitride semiconductors (GaN, AlN, InN) serve as foundational materials for modern optoelectronics, high-frequency microelectronics, and next-generation energy harvesting devices. However, traditional high-temperature epitaxy (>700 °C) introduces severe thermal stress, high dislocation densities, and fundamental incompatibility with flexible substrates or CMOS back-end-of-line (BEOL) processes. Plasma-enhanced atomic layer deposition (PEALD) provides a disruptive, ultra-low thermal budget (<300 °C) pathway for atomic-scale precision growth and conformal coating. This review systematically summarizes recent frontiers in PEALD-synthesized Group III-nitrides and 2D/3D polar heterostructures. First, we dissect the microscopic nucleation kinetics, surface bond reconstruction, and impurity suppression mechanisms across diverse substrates, including Si, sapphire, quartz, metals, and flexible polymers. Next, we highlight 2D template-assisted van der Waals epitaxy on graphene and MoS2, and elucidate polarization-driven dipole interactions and band alignment engineering at 2D/3D polar interfaces (e.g., α-In₂Se₃, Janus MoSSe). Furthermore, we comprehensively discuss innovative applications in advanced photovoltaics (as electron transport and passivation layers in perovskite and quantum dot-sensitized solar cells), silicon-based microcavity lasers, high-electron-mobility transistors (HEMTs), and flexible multimodal sensors. Finally, key technological challenges—including the low-thermal-budget paradox, wafer-scale uniformity, and deposition throughput—are addressed alongside future perspectives in area-selective ALD and neuromorphic computing, presenting a cohesive blueprint from underlying physics to macroscopic system integration.

Dark current is a critical parameter for infrared focal plane detectors, while practical measurement methods may exhibit temperature-dependent discrepancies. This study systematically evaluates the consistency between the blind cold shield (BCS) and theoretical coefficient (TC) methods using paired measurements of 24 mid-wave infrared detector chips at 120 K and 150 K, with 140 K measurements included as an intermediate experimental condition for descriptive analysis. Relative deviation and Bland–Altman analyses were employed to quantify inter-method consistency. At 120 K, 70.8% of chips showed TC dark-current values more than 20% below the BCS baseline, compared with 29.2% at 150 K. The mean absolute relative deviation decreased from 74.9% to 42.1%, while the geometric mean TC/BCS ratio increased from approximately 0.40–0.92. Bland–Altman analysis showed persistent absolute chip-to-chip variability, while the geometric mean TC/BCS ratio moved closer to unity at 150 K. These results indicate improved relative BCS–TC consistency over 120 K–150 K while emphasizing that the applicable measurement range is detector and configuration dependent.