Preparation and characteristic of ZnO thin film with high and low resistivity for an application of solar cell

Abstract

Al-doped zinc oxide (AZO) and undoped zinc oxide (UZO) films for the use as a transparent conductor and buffer layer of solar cell have been prepared using RF magnetron sputtering. Thin films with low resistivity can be achieved by using an Al-doped ZnO target, while films with high resistivity can be obtained by introducing an oxygen atmosphere during the deposition procedure. The AZO thin film shown with the lowest resistivity in this work was prepared with an RF power of 180 W, a sputtering pressure of 10 mTorr and a film thickness of 5000 Å that shows a resistivity of 1.4 × 10 − 4 Ω·cm and a transmittance of 95% in the visible range. On the other hand, the UZO film fabricated using reactive sputtering under a condition of more than 10% oxygen content exhibited the highest resistivity of 6 × 10 14 Ω·cm. We have expected that the fabricated AZO and UZO thin films in this work are suitable for the application of a buffer layer and transparent electrode of CIS solar cell.