Influence of Electrodes on the Parameters of Solar-Blind Detectors of UV Radiation

The influence of the topology of electrodes on the electrical and photoelectric characteristics of metal-semiconductor-metal structures is studied. Gallium-oxide films are produced by the radio-frequency magnetron-assisted sputtering of a Ga2O3 target onto (0001)-oriented sapphire substrates. Two types of electrodes are formed on the surface of the oxide films. The first type corresponded to two parallel electrodes spaced by an interelectrode distance of 250 mu m, and the second type to interdigitated electrodes. In the case of the second type of electrodes, the distance between the "fingers" is 50, 30, 10, and 5 mu m. The structures possess sensitivity to ultraviolet radiation at a wavelength of lambda = 254 nm, irrespective of the type of contact. The second type of detectors with an interelectrode distance of 5 mu m show the largest photocurrents, I-ph = 3.8 mA, and a specific detectivity of D* = 5.54 x 10(15) cm Hz(0.5) W-1.