Ultraviolet photoconductive detector based on epitaxial Mg0.34Zn0.66O thin films

We report on the fabrication and characterization of visible blind ultraviolet photodetectors based on MgxZn1-xO. Using pulsed laser deposition technique, Mg0.34Zn0.66O thin films with a bandgap of 4.05 eV were epitaxially grown on c-plane sapphire substrates. The structural, electrical, and optical properties of epilayers were characterized using various techniques. Based on the Mg0.34Zn0.66O films, planar geometry photconductive type metal-semiconductor-metal photodetectors were fabricated. At a 5 V bias, a high responsivity of 1200 A/W was achieved at 308 nm, and the visible rejection (R308 nm/R400 nm) was more than four orders of magnitude. The 10%-90% rise and fall time were 8 ns and 1.4 mus, respectively. (C) 2001 American Institute of Physics.