Papers by Keyword: Responsivity

Abstract: In recent years, MgZnO alloy becomes one of the most suitable materials for the fabrication of ultraviolet detectors. In this paper, we have fabricated three metal semiconductor metal (MSM) photodetectors on Mg_0.42Zn_0.58O film grown by radio frequency magnetron sputtering. The interdigital electrodes are 500 um long and 5 um wide with an interelectrode spacing 2, 5 and 10 um, respectively. The structural, electrical and optical properties of epilayers were characterized by various techniques. At 5 V bias, a peak responsivity of 1.09 mA/W was achieved at 283 nm for the device with 2 um interelectrode spacing. The peak responsivity at 283 nm increased with the reduction of the finger pitch for three devices and the ultraviolet-visible rejection ratio (R283 nm/R400 nm) was more than one order of magnitude at 5 V bias.

Abstract: In this article Tio2 thin film Containing dispersed Ag metal particle was prepared by the sol gel method, and the effect of the metal particles on the optical properties such as responsivity, extinction coefficient, plasmonic resonance of the thin films were investigated. UV/Vis optical spectra and Scanning electron microscopy were recorded to characterize the Ag/Tio2 composite films.

Abstract: The switching character of SiCGe/SiC heterojunction phototransistors with charge-compensation technique has been simulated with commercial simulator MEDICI. The influences of light power density, wavelength and carrier lifetime on switching characters were studied. Simulation result shown that the devices are latch-free device and fall time is much longer than rise time. The increasing of light power density and wavelength cause shorter rise time and longer fall time unless reaches SiCGe absorption edge 520nm, trade-off must made between responsivity and switching speed when carrier lifetime is considered, the ratio of them gets it maximum values at minority carrier lifetime equal 90ns.

Abstract: An n-SiC/p-SiCGe/n-SiCGe heterojunction phototransistor with charge compensation layer has been simulated with commercial simulator MEDICI. With wide bandgap SiC emitter and p-type SiCGe charge-compensation layer, device responsivity and breakdown voltage has been improved. It is found that with p-type SiCGe layer, the responsivity is nearly two times of without one. Furthermore, flat electrical field distribution during off-state enable it supports higher reverse bias, thus breakdown voltage increased from 450V to 580V for the given structure, and both breakdown voltage and responsivity increase with light absorption region length.

Abstract: The photo-response of 3C-SiC pn homojunction photodiodes was measured at high temperature up to 673K. At 473K, the response is hardly different from that at the room temperature. At 573K and 673K, the peak is red shift and lowering comparing that of 298K. The response increases on the long-wavelength region of the profile because of an increase in optical absorption coefficient on increase in temperature. Responsivities at various temperatures were calculated using one-dimensional diffusion model. The calculated profiles of response are qualitatively in agreement with the experimental results except for that of 473K.