A newly-designed photoelectrochemical self-powered detector is applied to an α-Ga 2 O 3 nanorod array to realize the detection of solar-blind ultraviolet light (wavelengths below 300 nm) and fast response (rise time of 0.076 s and decay time of 0.056 s).
Gallium oxide thin films were deposited by radio frequency magnetron sputtering technique. Structural, optical and photoelectrical properties of Ga2O3 thin films were investigated in detail. The as-grown Ga2O3 thin films were amorphous, while those annealed film were polycrystalline with monoclinic structure. Amorphous and polycrystalline gallium oxide metal-semiconductor-metal photodetectors were fabricated. However, annealed polycrystalline films have no photoresponse for deep ultraviolet light. The responsivity of the photodetector based on as-grown amorphous film is 122.7 μA/W at 256 nm and the ultraviolet (UV)-to-visible rejection ratios were 100, which indicates that the amorphous Ga2O3 thin films have potential application for solar-blind photodetector. High concentration of oxygen vacancies of amorphous film are considered to be responsible for photoresponse in amorphous gallium oxide thin films.
Cu-doped ZnO nanorods have been grown at 90°C for 90 min onto a quartz substrate pre-coated with a ZnO seed layer using a hydrothermal method. The influence of copper (Cu) precursor and concentration on the structural, morphological, and optical properties of ZnO nanorods was investigated. X-ray diffraction analysis revealed that the nanorods grown are highly crystalline with a hexagonal wurtzite crystal structure grown along the c-axis. The lattice strain is found to be compressive for all samples, where a minimum compressive strain of −0.114% was obtained when 1 at.% Cu was added from Cu(NO3)2. Scanning electron microscopy was used to investigate morphologies and the diameters of the grown nanorods. The morphological properties of the Cu-doped ZnO nanorods were influenced significantly by the presence of Cu impurities. Near-band edge (NBE) and a broad blue-green emission bands at around 378 and 545 nm, respectively, were observed in the photoluminescence spectra for all samples. The transmittance characteristics showed a slight increase in the visible range, where the total transmittance increased from approximately 80% for the nanorods doped with Cu(CH3COO)2 to approximately 90% for the nanorods that were doped with Cu(NO3)2.