An original self-powered UV photodetector integrating ZnO/CuCrO 2 core-shell nanowire heterostructures is fabricated using low-cost and scalable chemical deposition techniques operating at moderate temperatures. A 35 nm thick delafossite phase CuCrO 2 shell is formed with high uniformity by aerosol-assisted chemical vapor deposition over an array of vertically aligned ZnO nanowires grown by chemical bath deposition. The CuCrO 2 shell consists of columnar grains at the top of ZnO nanowires as well as nanograins with some preferential orientations on their vertical sidewalls. The ZnO/CuCrO 2 core-shell nanowire heterostructures exhibit significant diode behavior, with a rectification ratio approaching 1.2 × 10 4 at 1 V and -1 V, as well as a high optical absorptance above 85% in the UV part of the electromagnetic spectrum. A high UV responsivity at zero bias under low-power illumination of up to 3.43 mA W -1 under a 365 nm UV lamp, and up to 5.87 mA W -1 at 395 nm from spectrally resolved measurements, alongside a high selectivity with a UV-to-visible (395-550 nm) rejection ratio of 106 is measured. The short rise and decay times of 32 and 35 µs, respectively, both measured at zero bias, further establish these devices as promising candidates for cost-efficient, all-oxide self-powered UV photodetectors.
International audienceThermal Atomic Layer Deposition was used to deposit Al2O3 layers with thickness ranging from 2 to 100 nm for surface passivation of silicon solar cells. Various characterization techniques were used to evaluate the chemical, physical and optical properties of the layers and interfaces. Minority carrier lifetime around 2 ms was measured for an optimal thickness of 15 nm for as-deposited layers on high resistivity n-type silicon substrate. An annealing step at 400 degrees C increases lifetime up to 5.7ms for the same structure
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.