Diode UV detectors using oxide semiconductor thin films deposited by magnetron sputtering

摘要

This paper describes the fabrication of pn heterojunction thin-film diodes using polycrystalline oxide semiconducting thin films. Al-doped ZnO (AZO) and Mg-doped CuCrO_2 (CuCrO_2:Mg) thin films used as n- and p-type oxide semiconducting layers, respectively, were prepared on glass substrates by r.f. magnetron sputtering using a powder target. The resulting p-type CuCrO_2:Mg thin films prepared with a Mg content of 7 at.% exhibited a resistivity as low as 1.3X10~(-2)Ωcm and a band-gap energy of 3.3 eV. The voltage-current (Ⅴ-Ⅰ) characteristic of a pn junction fabricated using p~+-CuCrO_2:Mg and n~+-AZO thin films exhibited an ohmic, or linear, relationship. In addition, a pin heterojunction diode was fabricated by depositing high resistivity undoped ZnO and CuCrO_2 thin-film layers, or i-layers, between the n~+-AZO and the p~+-CuCrO_2:Mg thin-film layers. The resulting p~+-CuCrO_2:Mg/i-CuCrO_2/i-ZnO~+-AZO thin-film pin junction diode exhibited a rectifying Ⅴ-Ⅰcharacteristic and a photovoltage under UV light illumination.