Investigating the effect of Aluminum dopping on the structural, optical, electrical, and sensing properties of ZnO films

Abstract

More recently aluminum doped zinc oxide (ZnO:Al) thin films have attracted a lot of attention as an alternative to indium tin oxide (ITO) for optoelectronic devices in order to produce energy such as solar cells. In this work, ZnO:Al thin films were deposited onto quartz and silicon substrates by RF magnetron sputtering technique and the effect of Al doping on structural, optical and sensing properties of the films were studied. The dopant concentration was varied between 1 wt.% and 3 wt.% in the thin films. The crystalline structure of the films were investigated by X-ray diffraction, which indicated wurtzite structure along (100) plane. The surface morphology of the films characterized by AFM revealed that the grain size decreased with increasing dopant concentration.The films also exhibited changes in optical properties due to a decrease in band gap with increasing Al concentration. Hall measurement confirmed that the ZnO films exhibited an n-type conductivity. The results of gas sensing experiments showed that the sensitivity of the ZnO films for detecting CO2 enhanced with an increase in dopant concentration.

Phase and surface structures-optical transmittance correlation of sputtered Al-doped ZnO film on glass substrate

“…Aluminum-doped zinc oxide (AZO) thin films, an n-type semiconductor with a hexagonal wurtzite crystal structure, have attracted noteworthy interest from the researcher because of their distinctive optical and electrical properties with a wide range of applications and good stability. It is a non-toxic, lower-cost, and sustainable alternative to using as transparent conductive oxide (TCO) or an electron-transport layer (ETL) in applications for optoelectronic devices [1], and a coating layer for UV sensors [2], gas sensors [3], and heaters [4]. Various methods such as RF-sputtering [1][2][3][4], sol-gel dip coating [5,6], pulse laser deposition [7,8], and atomic layer deposition [9] have been used to prepare the AZO thin film on both a glass and flexible substrates.…”

“…It is a non-toxic, lower-cost, and sustainable alternative to using as transparent conductive oxide (TCO) or an electron-transport layer (ETL) in applications for optoelectronic devices [1], and a coating layer for UV sensors [2], gas sensors [3], and heaters [4]. Various methods such as RF-sputtering [1][2][3][4], sol-gel dip coating [5,6], pulse laser deposition [7,8], and atomic layer deposition [9] have been used to prepare the AZO thin film on both a glass and flexible substrates. Sputtering parameters such as power [10][11][12][13][14][15][16], pressure [11,12], and temperature [14] with substrate temperature [11,17] and substrate roughness [18] were important keys that have been intensively investigated to improve the optical and electrical properties of the AZO films.…”