MgxZn1a??xO Prepared by the Sola??Gel Method and Its Application for Ultraviolet Photodetectors

摘要： MgxZn1(cid:2)xO (x = 0.05, 0.10, 0.15, and 0.20) ?lms prepared on quartz substrates by the sol–gel method were characterized and studied. According to scanning electron microscopy and x-ray diffraction data, the MgxZn1(cid:2)xO ?lms exhibited a particle-stacking morphology and a hexagonal wurtzite crystal structure. An increase in Mg content led to an obvious increase in particle size. However, a weakening of the hexagonal wurtzite structure was observed and indicated the transition of the MgxZn1(cid:2)xO crystal structure, which was also con?rmed by the Raman spectra results. An increase in bandgap energy from 3.38 eV to 3.55 eV with increased Mg content was determined from the transmittance spectra. Ultraviolet photodetectors based on MgxZn1(cid:2)xO with interdigital electrodes were then fabricated. Dark current as low as 10 pA (corresponding to 5 nA/cm2) under bias of 10 V was achieved. A blueshift of the peak wavelength and cutoff wavelength was observed with increasing Mg content. Noise equivalent power as low as 2 9 10(cid:2)15 W was achieved, detectivity was found to be about 1.2 9 1011 cm Hz1/2/W, and quantum ef?ciency was nearly 100%, which was related to the photoconductive gain.