Enhanced-Performance Self-Powered Solar-Blind UV-C Photodetector Based on n-ZnO Quantum Dots Functionalized by p-CuO Micro-pyramids

Abstract

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.

Fluorinated Polyimide/Sepia Eumelanin Nanocomposites for Aerospace Applications

“…Although PI has superior high and low temperature resistance, insufficient transparency, photostability, and UV-shielding properties still limit its related applications. Transparency, corrosion resistance, high resistor, heat endurance, chemical stability, durability, ultraviolet shielding performance, and other extensive features make PI one of the “most development potential practical materials in this era”, − applied to a variety of sectors, including pellicle, PI fiber, thermal barrier, spacecraft, and more. − Charge transfer complexes (CTCs) contribute to UV shielding properties of PI. , However, it is worth noting that in an extreme lunar environment, the anti-UV aging and UV shielding ability of PI is far from being able to support the long-term use of PI and related products. As a result, superior PI-based UV shielding materials need to be developed urgently.…”

Pt/ZnGa2O4/p-Si Back-to-Back Heterojunction for Deep UV Sensitive Photovoltaic Photodetection with Ultralow Dark Current and High Spectral Selectivity

“…The performance of the Pt/ZnGa 2 O 4 /Si detector is compared with that of other DUV detectors in recent years (Table ). According to the comparison, it can be seen that the ultralow J D exhibited by this device is 2–3 orders of magnitude smaller than those of most DUV detectors. − At the same time, this device also displays a fast response speed and a large UV–vis rejection ratio, which are 1–2 orders of magnitude higher than those of most DUV photovoltaic detectors reported so far. , These excellent performances of this device can be attributed to the construction of the back-to-back barrier structure.…”

“…26−31 At the same time, this device also displays a fast response speed and a large UV−vis rejection ratio, which are 1−2 orders of magnitude higher than those of most DUV photovoltaic detectors reported so far. 29,31 These excellent performances of this device can be attributed to the construction of the back-toback barrier structure.…”

“…For specific procedures, we first epitaxially grew ZnGa 2 O 4 films with crystal orientation on Si substrates by the metal–organic chemical vapor deposition (MOCVD) method and then deposited ∼4 nm thick Pt transparent electrodes to fabricate high-performance Pt/ZnGa 2 O 4 /Si photovoltaic devices. At 0 V bias, the device showed a photoresponsivity of about 1.36 mA/W, a response speed of less than 50 ms, and a DUV–vis rejection ratio of 1.1 × 10 5 , which are 1–2 orders of magnitude higher than those of DUV photovoltaic detectors reported. − When the temperature was up to 470 K, the photo-to-dark current ratio (PDCR) of the device was >10 3 . In addition, compared with Au/ZnGa 2 O 4 /Si heterojunction devices, Pt/ZnGa 2 O 4 /Si heterojunction devices presented a lower dark current density (∼9.6 × 10 –5 μA/cm 2 ) and a higher PDCR (>10 5 ).…”

Self-Powered Solar-Blind UV Detectors Based on O-Terminated Vertical Diamond Schottky Diode with Low Dark Current, High Detectivity, and High Signal-to-Noise Ratio

“…This shows that the detectors have typical solar-blind characteristics. The detectivity ( D *) considers the influence of I dark on the detection sensitivity of the detector: D * = R /((2 qJ dark )^(1/2)), where J dark is the dark current density of the detector. The unit of D* is cm Hz 1/2 W –1 or Jones.…”