Nanocrystalline p-type transparent Cu–Al–O semiconductor prepared by chemical-vapor deposition with Cu(acac)2 and Al(acac)3 precursors

Abstract

P-type transparent copper–aluminum–oxide semiconductor films are prepared by the use of the chemical-vapor deposition (CVD) technique with Cu(acac) 2 and Al(acac) 3 precursors. Transmission electron microscopy and electron diffraction suggest that the films contain nanocrystalline phases of CuAlO 2 and Cu 2 O , in which CuAlO 2 is dominant. Both Hall technique and Seebeck measurement reveal that the film is p type, and a very high room-temperature conductivity of 2 S cm−1 is achieved. This success of high-conductive p-type transparent semiconductor using CVD further paves the way for transparent semiconductor p–n junctions as well as industrial mass production of the relevant devices. The Hall measurement of the film shows a sheet mobility of 0.16 cm2 V−1 S−1 and a carrier concentration of 1.8×10 19 cm −3 . A wide optical gap of 3.75 eV due to quantum confinement is found, and the activation energy for the positive holes is 0.12 eV.