Optical and Electrical Properties of Mn-doped and Mn–Al co-doped ZnO Thin Films Annealed at Different Temperatures for Photosensor Applications

Abstract

Mn-doped and Mn-Al co-doped zinc oxide (ZnO) thin films were deposited on glass substrates by RF magnetron sputtering at room temperature. The X-ray diffraction results revealed that both films consisted of a single phase and had a wurtzite structure with a c-axis orientation. The electrical properties, transmittance characteristics, surface properties, and crystal structures of the films were investigated following annealing at temperatures ranging from 200 to 500 °C. The results showed that the as-deposited Mn:ZnO thin film had an average transmittance of 83%. The transmittance increased to 85% following annealing at 500 °C. The as-deposited Mn-Al co-doped ZnO thin film had a low transmittance of only 40%. However, after annealing at 500 °C, the transmittance increased to 83%. The annealed Mn-Al:ZnO thin film also showed a low electrical resistivity of 1.75 × 10 −3 Ω•cm, an electron mobility of 20.8 cm 2 V −1 s −1 , and a carrier concentration of 5.3 × 10 20 cm −3 . Scanning electron microscopy (SEM) results showed that the crystal size of both thin films increased following annealing. Owing to their good optical and electrical properties, the annealed Mn-Al:ZnO thin films can be used as photosensor materials.

Optical and Electrical Properties of ITO:Ga/Ag Double-layer Thin Films for Photosensor Applications

“…(14) In the pursuit of higher optical transmittance and electrical performance, many recent studies have proposed the formation of a metal/oxide double-layer film structure comprising an oxide film and a metal film. (15)(16)(17)(18) Such double-layer films are configured to suppress the reflection of visible light by the metal layer and therefore have relatively high transmittance. (19) It has also been shown that a metal film of less than 15 nm thickness tends to form an island film, that a multilayer film formed with such a metal film and an oxide film can be annealed to inhibit the formation of the island structure by the metal film, and that the thermal diffusion during annealing enables strong bonding between the oxide film and the metal film, which contributes to increased conductivity and optical transmittance.…”