Structural and electrical properties of Zn_1–xCu_x O thin films

Abstract

Producing p ‐type ZnO is one of the key issues in developing ZnO‐based electronic devices. The substitution of monovalent Cu ions on Zn sites have been theoretically proposed, and experimental studies were carried out using Zn1–xCux O with small Cu contents (x ≤ 0.1). However, material properties Zn1–xCux O with a large Cu content have not been revealed. In this article, we present the electrical properties of Zn1–xCux O thin films with large x up to 0.75 fabricated using a monovalent Cu source along with their structural properties, as deduced from elemental analyses and crystallographic studies. The experimental results derived from electrical conductivity and thermoelectric measurements are discussed with a focus on controllability of p ‐type conductivity, specifically under O‐rich conditions. Finally, carrier concentrations are discussed from the capacitance–voltage plots of p ‐Zn1–xCux O/n ‐Si heterojunction diodes. (© WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Physical Properties of p-Type Tin Monoxide Films Deposited at Low Temperature by Radio Frequency Magnetron Sputtering

“…SnO films were deposited on fused quartz substrates by rf magnetron sputtering with a sputtering power of 300 W and a deposition pressure of 9.3 Pa. 10) The substrate temperature T sub was varied in the range 60-220 C. Argon was used as the sputtering gas and the typical sputtering rate was 4 nm/s. A 3N SnO powder was used as a sputtering source.…”

“…Details of the X-ray diffraction (XRD) system equipped with a Cu K source, a field-emission scanning electron microscope (FESEM), a Hall measurement system using the van der Pauw configuration, thermoelectric measurements, transmittance spectroscopy, and photoacaustic (PA) spectroscopy used to characterize the SnO films are described elsewhere. 10,11) XRD patterns of the SnO films formed at different T sub values are presented in Fig. 1(a).…”