N-TYPE ELECTRICAL-CONDUCTION IN TRANSPARENT THIN-FILMS OF DELAFOSSITE-TYPE AGINO2

Thin films of AgInO2 were prepared to find a transparent and n-type co nducting oxide with a delafossite structure. This is a candidate mater ial for fabricating a pn junction with the recently found p type condu cting and transparent CuAlO2 delafossite. Nondoped and 5% Sn-doped thi n films were deposited on a silica glass substrate by radio-frequency sputtering. The crystalline phase in the films was identified to be th e delafossite structure by x-ray diffraction and chemical composition was confirmed to be an Ag/In ratio = 1.00/0.97 by inductively coupled plasma emission spectroscopy. The optical band gap was estimated from absorption spectra to be similar to 4.4 eV, and the thin films were tr ansparent up to near ultraviolet region. Electrical conductivities of the nondoped and 5% Sn-doped AgInO2 films at room temperature were 1x1 0(-5) and 6x10(0) S cm(-1), respectively. Measurements of Hall voltage and Seebeck coefficient (-50 mu V K-1) suggested the conduction in th e Sn-doped film to be n type. Carrier concentration and Hall mobility in the doped film were 2.7x10(19) cm(-3) and 0.47 cm(2) V-1 s(-1), res pectively. (C) 1998 American Institute of Physics.