Experimental Studies on Doped and Co-Doped ZnO Thin Films Prepared by RF Diode Sputtering

Abstract

For decades zinc oxide (ZnO) has been in the spotlight due to its unique combination of semiconductor, piezoelectric, optical, and magnetic properties, which open perspectives for wide range of applications from optoelectronic and transparent electronic devices (Ohta & Hosono, 2004), surface and bulk acoustic wave devices and piezoelectric transducers (Wang et al., 2008), spintronics (Ji et al., 2008), to chemical and gas sensors (Carotta et al., 2009), and solar cells (Ganguly et al., 2004). Great industrial advantages of ZnO are its eco-friendly nature, wide abundant sources and low costs of metal Zn. ZnO is a group II-VI semiconductor with a direct band gap of 3.37 eV at room temperature, which can be modified (∼3 eV– 4 eV) via extrinsic doping with either cadmium (Cd) or magnesium (Mg). By its semiconductor properties ZnO is similar to gallium nitride (GaN) (Table 1).