Effect of Al~(3+)/Si~(4+) codoping on the structural, optoelectronic and UV sensing properties of ZnO

摘要

The structural, vibrational, and optoelectronic properties of sol-gel synthesized Zn_(1-x)(Al_(0.5)Si_(0.5))_xO nanoparticles were investigated. The X-ray diffraction studies of the samples confirmed the hexagonal wurtzite phase with the space group P6_3mc. No significant changes were observed in the lattice parameters. The increase in the intensity of E_(high)~2 Raman mode observed at 438 cm~(-1) indicates a decrease in the crystallite size. The reduction in the deep-level emission band with the introduction of Al/Si indicates a decrease in intrinsic defects for the codoped sample. A unique electron paramagnetic resonance signal at g = 1.96 follows the same trend as the green luminescence, and its evolution was shown to probe the oxygen vacancy concentrations. I-V characteristics curve confirm the increase in the conductivity for the codoped samples. To evaluate the role of surface defects, ultraviolet photoresponse behavior as a function of time was also studied, and an increase in the photocurrent was observed. The slow decay and rise in the photocurrent are because of multiple trapping by interstitial defects. A relatively faster response time was observed with the substitution of Al/Si. It has been observed that prepared nanomaterials are suitable for optoelectronic devices.