RESUMO
Optoelectronic devices have various applications in medical equipment, sensors, and communication systems. Photodetectors, which convert light into electrical signals, have gained much attention from many research teams. This study describes a low-cost photodetector based on CuO nanoparticles and ZnO nanorods operating in a wide range of light wavelengths (395, 464, 532, and 640 nm). Particularly, under 395 nm excitation, the heterostructure device exhibits high responsivity, photoconductive gain, detectivity, and sensitivity with maximum values of 1.38 A·W-1, 4.33, 2.58 × 1011 Jones, and 1934.5% at a bias of 2 V, respectively. The sensing mechanism of the p-n heterojunction of CuO/ZnO is also explored. Overall, this study indicates that the heterostructure of CuO nanoparticles and ZnO nanorods obtained via a simple and cost-effective synthesis process has great potential for optoelectronic applications.
RESUMO
We showed well-aligned zinc oxide (ZnO) nanorod arrays synthesized using hydrothermal method at atmospheric pressure. The influence of fabrication conditions such as Zn2+/hexamethylentriamin concentration ratio, and growth temperature on the formation of ZnO nanorods was investigated. Scanning Electron Microscope (SEM) images and X-ray Diffraction (XRD) analysis were used to confirm the single crystal of ZnO nanorods, which showed wurtzite structure with growth direction of [0001] (the c-axis). Photoluminescence (PL) measurements of ZnO nanorods revealed an intense ultraviolet peak at 388.5 nm (3.19 eV) at room temperature. The results showed that the ZnO seed layers had strong influence on the growth of vertically aligned ZnO nanorods. The gas sensor based on ZnO nanorod arrays had the most selectivity with n-butanol gas (within 2 surveyed gas: ethanol and n-butanol) and showed a higher sensitivity of 222, fast response time of 15 seconds, recovery time of 110 seconds and lower operating temperature of 200-250 °C than the sensor based on the ZnO film in the same detecting conditions.