Ultrahigh quantum efficiency of CuO nanoparticle decorated In2Ge2O7 nanobelt deep-ultraviolet photodetectors
ABSTRACT Although there has been significant progress in the fabrication and performance optimization of 1-D nanostructure-based deep-ultraviolet photodetectors, it is still a challenge to develop an effective device with high performance characteristics, such as high photocurrent-dark current ratio and high quantum efficiency. Herein, an efficient and simple method to fabricate high performance CuO nanoparticle decorated In(2)Ge(2)O(7) nanobelt deep-ultraviolet photodetectors is presented. A CuO coated In(2)Ge(2)O(7) nanobelt based photodetector showed very high responsivity (7.34 × 10(5) A W(-1)) and high quantum efficiency (3.5 × 10(6)). The underlying mechanism is proposed to be the formation of p-n heterojunctions between decorated nanoparticles and nanobelts, which enhances the spatial separation of photogenerated electrons and holes. This study opens up a new horizon for creation of novel photodetectors with high quantum efficiency.
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ABSTRACT: Using lattice matched ZnO substrates, wurtzite single crystalline Mg <sub>0.49</sub> Zn <sub>0.51</sub> O films were obtained by reactive magnetron cosputtering method, and the heterostructures of MgZnO/ZnO were fabricated into metal-semiconductor-metal solar-blind photodetectors (SBPDs). Calculated and experimental results demonstrate that the response of the ZnO substrate can be suppressed by adopting a thick MgZnO epilayer. The SBPD with a 2 μ m thick MgZnO epilayer shows a peak responsivity of 304 mA/W at 260 nm under 10 V bias, which is comparable to the highest value ever reported in MgZnO-based SBPDs. A rejection ratio (R260 nm/R365 nm) over 5×10<sup>2</sup> is also observed, indicating fully suppression of the signal from ZnO substrate.Applied Physics Letters 06/2011; 98(22-98):221112 - 221112-3. DOI:10.1063/1.3596479 · 3.52 Impact Factor
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ABSTRACT: The ternary oxides, Zn2GeO4 and In2Ge2O7 nanowires, are promising n-type semiconductors with outstanding transport properties for high performance electronic devices. By using the direct contact printing process, we reported the assembly of horizontally aligned Zn2GeO4 and In2Ge2O7 nanowire arrays to be used as building blocks for high performance multi-channel field-effect transistors. The as-fabricated multi-channel transistors exhibited higher voltage stability and repeatability than their single nanowire based counterparts. The effective mobilities of the multi-channel field-effect transistors were calculated to be 25.44 cm2 V−1 s−1 and 11.9 cm2 V−1 s−1, comparable to the single-channel FETs. The as-fabricated multi-channel transistors were also used as high performance photodetectors, exhibited a high sensitivity to ultraviolet light illumination with a photoconductive gain and quantum efficiency as high as 1.034 × 105 and 1.032 × 107% for Zn2GeO4 nanowires and 2.58 × 105 and 2.617 × 107% for In2Ge2O7 nanowires.11/2012; 1(1):131-137. DOI:10.1039/C2TC00055E
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ABSTRACT: The deep ultraviolet detecting property of AlxZn1−xO (AZO) alloy thin film as photocathode layer was investigated. This AZO thin film was deposited via RF magnetron sputtering using a ceramic target, in which the concentration of Al was about 30at%. UV/dark contrast nearly three orders of magnitude has been achieved by using it in a simply fabricated photodetector, under 254 nm UV illumination with power of 0.5 mW/cm2 and bias of 80 V. The photocurrent can be generated even without external electric field after illumination and come to saturation when the bias reaches 80 V. Conventional UV emission peak around 380 nm in photoluminescence spectra of ZnO is absent in the AZO thin film. Optical band gap of the AZO thin film is estimated to be 4.41 eV and corresponding cutoff wavelength is 281 nm. Negative surface potential of this thin film that enables high emitting efficiency is detected using Kelvin probe microscope, due to the elimination of surface barrier.Journal of Alloys and Compounds 06/2013; 563:99–103. DOI:10.1016/j.jallcom.2013.02.078 · 2.73 Impact Factor