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Wide bandgap semiconductor AlGaN alloys have been identified as key materials to fabricate solar-blind ultraviolet photodetectors (SBUV PDs). Herein, a self-driven SBUV polarization-sensitive PD (PSPD) based on semipolar (112̅2)-oriented AlGaN films is reported. Using the flow-rate modulation epitaxy method, the full widths at half maximum (FWHMs) for the obtained (112̅2) AlGaN along [112̅3̅] and [11̅00] rocking curves are 0.205° and 0.262°, respectively, representing the best results for heteroepitaxial semipolar AlGaN so far. Density functional theory calculations and experimental results reveal that semipolar AlGaN possesses in-plane anisotropy. The self-driven (112̅2) AlGaN PSPDs exhibit strong polarization-sensitive photoresponse with a polarization ratio of 1.54 at 266 nm and rapid response of 450/450 ms compared to other low-dimensional semiconductor materials. More interestingly, we observe positive and negative photoresponse behaviors under UV light illumination due to surface states and charge transfer. Our results may enable potential applications in multifunctional SBUV optoelectronic devices.
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http://dx.doi.org/10.1021/acsami.4c18352 | DOI Listing |
Langmuir
September 2025
College of Physics, Nanjing University of Aeronautics & Astronautics, No. 29 Jiangjun Rd, Nanjing 211106, People's Republic of China.
Surface activation is pivotal for achieving aluminum gallium nitride photocathode with low surface affinity, yet optimizing composition, adsorbates, and coverage is highly intricate. Using the (001) surface as a model, we constructed 625 configurations spanning Al component (0-1), coverage (0-1 ML), and coadsorption of main-group atoms (Li-Cs). Density-functional theory calculations of adsorption energy and work function served as the learning targets.
View Article and Find Full Text PDFNat Commun
September 2025
State Ley Laboratory of Integrated Optoelectronics, Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, School of Physics, Northeast Normal University, Changchun, China.
Single-pixel imaging is emerging as a promising alternative to traditional focal plane array technologies, offering advantages in compactness and cost-effectiveness. However, the lack of solar-blind photodetectors combining fast-response and high-sensitivity has constrained their application in the deep ultraviolet spectrum. This work introduces a self-powered solar-blind photodetector based on a heterostructure comprising a GaO photosensitive layer, an AlN barrier layer, and an N-polar AlGaN:Si contact layer.
View Article and Find Full Text PDFMicromachines (Basel)
July 2025
State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xidian University, Xi'an 710071, China.
AlGaN-based high-electron-mobility transistors are critical for next-generation power electronics and radio-frequency applications, yet achieving stable enhancement-mode operation with a high threshold voltage remains a key challenge. In this work, we designed p-AlGaN superlattices with different structures and performed energy band structure simulations using the device simulation software Silvaco. The results demonstrate that thin barrier structures lead to reduced acceptor incorporation, thereby decreasing the number of ionized acceptors, while facilitating vertical hole transport.
View Article and Find Full Text PDFMonolithic integration of micro-light emitting diodes (LEDs) arrays, waveguide, and photodiodes (PD) was achieved on 275 nm deep-ultraviolet (DUV) LED epitaxial wafers, enabling self-monitoring LED arrays. It revealed significant size-dependent effects on the electrical and optical characteristics of LEDs. Arrays with mesa diameters of 220 m, 140 m, and 60 m exhibited enhanced current spreading, where the 60-m devices achieved peak external quantum efficiency (EQE) of 4.
View Article and Find Full Text PDFUltramicroscopy
August 2025
Univ. Grenoble Alpes, CEA, LETI 38000 Grenoble, France.
Recent advancements in high-resolution spectroscopy analyses within the scanning transmission electron microscope (STEM) have paved the way for measuring the concentration of chemical species in crystalline materials at the atomic scale. However, several artifacts complicate the direct interpretation of experimental data. For instance, in the case of energy-dispersive X-ray (EDX) spectroscopy, the linear dependency of local X-ray emission on composition is disrupted by channeling effects and cross-talk during electron beam propagation.
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