Epitaxial Zinc Stannate (Zn2SnO4) Thin Film for Solar Cells

Epitaxial Zn2SnO4 thin films were fabricated using rf magnetron sputtering and characterized via X-ray diffraction (XRD) to investigate its structural behaviors. XRD measurements indicate high-quality single crystal films of (400) orientation. The growth follows cubic-to-cubic alignment with the epitaxial relationship of Zn2SnO4[001]//MgO[001] in the out-of-plane direction and Zn2SnO4[110]//MgO[110] in the in-plane direction. The Hall mobility of 88.5 +/- 6.2 cm(2) V-1 s(-1) was achieved. The Zn2SnO4 films had average optical transmittance >= 90% and a band gap of 3.582 +/- 0.082 eV. In the optical pump-THz probe spectroscopy result, a relatively longer charge-carrier lifetime, tau(1) = 2158.89 ps, was achieved.