A high-performance vertically injected broadband UV-to-IR photodetector based on Gd-doped ZnO nanorods (NRs)/CHNHPbI perovskite heterojunction was fabricated on metal substrates. Our perovskite-based photodetector is sensitive to a broad spectral range, from ultraviolet to infrared light region (λ = 250-1357 nm). Such structure leads to a high photoresponsivity of 28 and 0.22 A/W, for white light and IR illumination, respectively, with high detectivity values of 1.1 × 10 and 9.3 × 10 Jones. Optical characterizations demonstrate that the IR detection is due to intraband transition in the perovskite material. Metal substrate boosts carrier injection, resulting in higher responsivity compared to the conventional devices grown on glass, whereas the presence of Gd increases the ZnO NRs performance. For the first time, the perovskite-based photodetector is demonstrated to extend its detection capability to IR (>1000 nm) with high room temperature responsivity across the detected spectrum, leading to a high-performance ingenious cost-effective UV-to-IR broadband photodetector design for large-scale applications.

We demonstrate a state-of-the-art high-efficiency GaN-based vertical light-emitting diode (VLED) grown on a transparent and conductive (-201)-oriented (β-GaO) substrate, obtained using a straightforward growth process that does not require a high-cost lift-off technique or complex fabrication process. The high-resolution scanning transmission electron microscopy (STEM) images confirm that we produced high quality upper layers, including a multiquantum well (MQW) grown on the masked β-GaO substrate. STEM imaging also shows a well-defined MQW without InN diffusion into the barrier. Electroluminescence (EL) measurements at room temperature indicate that we achieved a very high internal quantum efficiency (IQE) of 78%; at lower temperatures, IQE reaches ∼86%. The photoluminescence (PL) and time-resolved PL analysis indicate that, at a high carrier injection density, the emission is dominated by radiative recombination with a negligible Auger effect; no quantum-confined Stark effect is observed. At low temperatures, no efficiency droop is observed at a high carrier injection density, indicating the superior VLED structure obtained without lift-off processing, which is cost-effective for large-scale devices.

in a wide range of industrial applications, such as homeland security, medical diagnostics, food curing, sanitation, chemical and biological threat detection, space-tospace communications, missile detection, military surveillance, target detection and acquisition, transparent thin-film transistors, solar cells, white lighting, sterilization, medical treatment, and touch display panels. [1][2][3][4][5][6][7] For example, the most commercial DUV photodetectors are produced using UV-enhanced narrow bandgap semiconductors, mainly Si-based photodetector. [8,9] However, the narrow bandgap materials are ineffective in rejecting signals in the UV−vis−IR spectral region, making them unsuitable for DUV applications. Thus, high-quality DUV WBGSs are still needed to produce high-performance DUV optoelectronic devices. In each of the aforementioned fields, scientists and industry practitioners are looking to overcome different challenges. There is a growing demand for both p-type and n-type WBGSs that possess good stability and conductivity. The main obstacle to the achievement of this goal stems from the lack of p-type wide bandgap materials operating in the DUV range below 300 nm (i.e., >4.1 eV) that exhibit good p-type stability. Currently, the p-type materials having bandgap in the UV-A range (such as p-type GaN, Cu 2 O, and SnO) are utilized in DUV optoelectronics, which severely downgrade device performance, as their bandgaps are limited to the UV-A-to-visible spectral region (320-400 nm). [10,11] Moreover, though n-type WBGSs (e.g., ZnO, Ga 2 O 3 , and AlGaN) with good conductivity and stability can operate in the UV and DUV range (280−390 nm), it is not possible to convert them to a p-type material with good stability and conductivity due to their intrinsic electronic properties. [2,6,[11][12][13][14][15][16] Consequently, no highly stable conductive p-type DUV WBGS operating in both UV-B and UV-C region presently exists. [17] Further advances in the field of DUV optoelectronics are hindered by other issues, such as the difficulty in developing new cost-effective material production and fabrication methods that could replace the expensive and high vacuum-based technologies presently in use. Thus, as DUV-WBGS based devices tend Wide bandgap semiconductor (WBGS)-based deep UV (DUV) devices lag behind those operating in the visible and IR range, as no stable p-type WBGS that operates in the DUV region (<300 nm) presently exists. Here, solutionprocessed p-type manganese oxide WBGS quantum dots (MnO QDs) are explored. Highly crystalline MnO QDs are synthesized via femtosecond-laser ablation in liquid. The p-type nature of these QDs is demonstrated by Kelvin probe and field effect transistor measurements, along with density functional theory calculations. As proof of concept, a high-performance, self-powered, and solar-blind Schottky DUV photodetector based on such QDs is fabricated, which is capable of detecting under ambient conditions. The carrier collection efficiency is enhanced by asymmetric electrode structure, leadi...

Enhanced ultraviolet (UV) photodetectors (PDs) with high responsivity comparable to that of visible and infrared photodetectors are needed for commercial applications. n-Type ZnO nanotubes (NTs) with high-quality optical, structural, and electrical properties on a p-type Si(100) substrate are successfully fabricated by pulsed laser deposition (PLD) to produce a UV PD with high responsivity, for the first time. We measure the current-voltage characteristics of the device under dark and illuminated conditions and demonstrated the high stability and responsivity (that reaches ∼101.2 A W) of the fabricated UV PD. Time-resolved spectroscopy is employed to identify exciton confinement, indicating that the high PD performance is due to optical confinement, the high surface-to-volume ratio, the high structural quality of the NTs, and the high photoinduced carrier density. The superior detectivity and responsivity of our NT-based PD clearly demonstrate that fabrication of high-performance UV detection devices for commercial applications is possible.

All-inorganic lead halide perovskites are promising materials for many optoelectronic applications. However, two issues that arise during device fabrication hinder their practical use, namely inadequate continuity of coated inorganic perovskite films across large areas and inability to integrate these films with traditional photolithography due to poor adhesion to wafers. Herein, for the first time, to address these issues, we show a room-temperature synthesis process employed to produce of CsPbBr 3 perovskite nanocrystals with twodimensional (2D) nanosheet features. Due to the unique properties of these 2D nanocrystals, including the "self-assembly" characteristic, and "double solvent evaporation inducing selfpatterning" strategy are used to generate high-quality patterned thin films in selected areas automatically after-drop-casting, enabling fabrication of high-performance devices without using complex and expensive fabrication processing techniques. The films are free from

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Smart solar-blind UV-C band photodetectors suffer from low responsivity in a self-powered mode. Here, we address this issue by fabricating a novel enhanced solar-blind UV-C photodetector array based on solution-processed n-ZnO quantum dots (QDs) functionalized by p-CuO micro-pyramids. Self-assembled catalyst-free p-CuO micro-pyramid arrays are fabricated on a pre-ablated Si substrate by pulsed laser deposition without a need for a catalyst layer or seeding, while the solution-processed n-ZnO QDs are synthesized by the femtosecond-laser ablation in liquid technique. The photodetector is fabricated by spray-coating ZnO QDs on a CuO micro-pyramid array. The photodetector performance is optimized via a p–n junction structure as both p-ZnO QDs and p-CuO micro-pyramid layers are characterized by wide band gap energies. Two photodetectors (with and without CuO micro-pyramids) are fabricated to show the role of p-CuO in enhancing the device performance. The n-ZnO QD/p-CuO micro-pyramid/Si photodetector is characterized by a superior photo-responsivity of ∼956 mA/W at 244 nm with a faster photoresponse (<80 ms) and 260 nm cut-off compared to ZnO QDs/Si photodetectors, confirming that the p-CuO micro-pyramids enhance the device performance. The self-powered photoresponse with a high photo-responsivity of ∼29 mA/W is demonstrated. These high-responsivity solar-bind UV-C photodetector arrays can be used for a wide range of applications.

and military devices. Among these applications, medical diagnostics is particularly significant, but it presently requires direct exposure to high doses of radiation, which is harmful to human health, increasing cancer risk, especially in children. [1,2] Hence, X-ray detectors possessing both high sensitivity and high resolution with a low light interface noise [3,4] are required to minimize the radiation exposure during routine medical diagnostics. In the pertinent literature, use of conventional semiconductors for direct X-ray detection has been reported by several groups, including amorphous Se, [5] crystalline Si, [6] Ge, [7] HgI 2 , [8] CdTe, [9,10] and CdZnTe, [9,10] indicating that the most effective materials are indirect bandgap semiconductors [5-10] that exhibit low light interference noise. However, as such devices possess low sensitivity due to the low atomic number values of their materials, [7] as well as they still require expensive fabrication and complex processing methods, there is a high industrial demand for cost-effective highly sensitive X-ray detectors that are more suited for mass production. Ionic perovskite crystals can be processed from solution at low temperatures, in contrast to covalent bond semiconductors, which require a high-temperature crystallization process. Consequently, lead halogen perovskite has emerged as a promising candidate due to its cost-effectiveness, high crystal quality, high absorption cross-section, high illumination, and ability to form High-energy radiation detectors such as X-ray detectors with low light photoresponse characteristics are used for several applications including, space, medical, and military devices. Here, an indirect bandgap inorganic perovskite-based X-ray detector is reported. The indirect bandgap nature of perovskite materials is revealed through optical characterizations, time-resolved photoluminescence (TRPL), and theoretical simulations, demonstrating that the differences in temperature-dependent carrier lifetime related to CsPbX 3 (X = Br, I) perovskite composition are due to the changes in the bandgap structure. TRPL, theoretical analyses, and X-ray radiation measurements reveal that the high response of the UV/visible-blind yellow-phase CsPbI 3 under high-energy X-ray exposure is attributed to the nature of the indirect bandgap structure of CsPbX 3. The yellowphase CsPbI 3-based X-ray detector achieves a relatively high sensitivity of 83.6 μCGy air −1 cm −2 (under 1.7 mGy air s −1 at an electron field of 0.17 V μm −1 used for medical diagnostics) although the active layer is based solely on an ultrathin (≈6.6 μm) CsPbI 3 nanocrystal film, exceeding the values obtained for commercial X-ray detectors, and further confirming good material quality. This CsPbX 3 X-ray detector is sufficient for cost-effective device miniaturization based on a simple design.