ERBIUM-DOPED INDIUM OXIDE-FILMS PREPARED BY RADIO-FREQUENCY SPUTTERING

Er doping of conducting oxide films has been investigated. Erbium-dope d indium oxide films were prepared by rf magnetron sputtering. The dep osited films were characterized in terms of electrical, optical, and s tructural properties. The Er-doped indium oxide films are highly (222) -oriented normal to the substrate surface and show a resistivity in th e range of 10(-3)-10(3) Ohm cm. The Er-doped conducting (or semiconduc ting) oxide films are optically active, i.e., show a clear room-temper ature photoluminescence at 1.54 mu m, corresponding to intratransition s in Er3+ ions. Compared with the undoped indium oxide films, the erbi um doping is found to have the effect of increasing the resistivity (u p to two orders of magnitude) of the films, mainly via a reduction of carrier concentration. Post-deposition annealing in air ambient signif icantly enhances bath the Er3+ luminescence and Hall mobility (up to 6 0 cm(2)/V s), and reduces the carrier concentration. The enhancement o f Hall mobility is attributed to a reduction of grain boundaries and v oids with the anneal treatment as supported by the x-ray diffraction m easurement results. Post-deposition annealing in reducing ambient (N-2 /H-2) decreases the resistivity dramatically mainly via an increase of carrier concentration (up to 10(20) cm(-3)), and also enhances the Er 3+ luminescence.