Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires: a novel approach | Nanoscale Res Lett 2007 2 161-167 DOI S11671-007-9048-6 NANO EXPRESS Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires a novel approach S. S. Hullavarad N. V. Hullavarad P. C. Karulkar A. Luykx P. Valdivia Published online 3 March 2007 to the authors 2007 Abstract The ZnO nanostructures consisting of micro spheres in a network of nano wires were synthesized by direct vapor phase method. X-ray Photoelectron Spectroscopy measurements were carried out to understand the chemical nature of the sample. ZnO nanostructures exhibited band edge luminescence at 383 nm. The nanostructure based ZnO thin films were used to fabricate UV sensors. The photoresponse measurements were carried out and the responsivity was measured to be 50 mA W-1. The rise and decay time measurements were also measured. Keywords UV Sensor Nano structures Microspheres Nanowire network Rise Decay time Photoresponse Photoluminescence Introduction Zinc oxide ZnO is a promising wide bandgap semiconductor for applications in ultra violet UV light emitting devices and sensors 1 . ZnO is a direct bandgap Eg eV semiconductor with a large exciton binding energy 60 meV 2 exhibiting near UV emission transparent conductivity 3 and piezoelectricity 4 . The high exciton binding energy in ZnO S. S. Hullavarad El N. V. Hullavarad P. C. Karulkar Office of Electronic Miniaturization University of Alaska Fairbanks Fairbanks AK 99701 USA e-mail fnssh1@ A. Luykx P. Valdivia Center for Superconductivity Research University of Maryland College Park MD 20742 USA crystal can ensure an efficient excitonic emission at room temperature under low excitation intensity which has potential applications in high efficiency light emitting diodes and UV lasers. ZnO has been widely reported as a visible blind UV sensor 5 over a wide range of applications in military and non-military arenas 6 that includes missile plume detection for hostile missile tracking flame sensors UV source .
