N Doping and Al-N Co-doping in Sol–Gel ZnO Films: Studies of Their Structural, Electrical, Optical, and Photoconductive Properties

Abstract

We have studied the structural, electrical, optical, and optoelectronic properties of N-doped and Al-N co-doped ZnO films grown by sol-gel technique. Both the undoped and doped films have a hexagonal wurtzite-type structure. The undoped film shows a very low electron concentration. The N-doped film exhibits an anomalous conduction type, while the Al-N co-doped film shows relatively stable p-type conduction. Though the transparency in the visible region is retained in the doped films, its optical qualities are degraded as indicated by photoluminescence results. The N-doped film has better response to ultraviolet light compared with the undoped and co-doped films. These results are important for the growth and development of p-type ZnO films using the very low-cost sol-gel method.

Facile synthesis of highly oriented p-type aluminum co-doped zinc oxide film with aqua ammonia

“…High resistivity was observed from the films without co-doping. The films co-doped with aluminium possess an acceptable resistivity with Hole concentration in the 10 17 cm −3 and resistivity range between 45 and 62 cm 2 /V s. These results correlate well with data published by Ge and Dutta [20,33]. Fig.…”

“…The EDX data also shows that the sputtered film had incorporated most nitrogen and the ZnO:Al:N (NH 4 OH) the least. Dutta et al [33] has suggested that NH 3 readily escapes from ammoniac solution, unless the experiment is conducted under airtight condition. During the sputtering process, the chamber had been evacuated into high vacuum (10 −6 Torr).…”

“…However, few studies on the sol-gel synthesis of p-type NZO are available in the literature. Dutta et al [33] obtained a stable and conductive p-type NZO by co-doping of N with Al through sol-gel process, without investigating the effects of chemical compounds selection on the property of NZO. Indeed, the published results from the sol-gel synthesis of ZnO-related films have confirmed that the chemical compounds selection has a significant effect on the structure, optical and electrical properties of the film [34].…”

Optical properties of Zn1−x Al x O:NiO transparent metal oxide composite thin films prepared by sol–gel method

“…However, the biggest challenge to achieve the ZnO-based optoelectronic devices is the difficulty to fabricate reliable p-type ZnO. In previous studies, many efforts focuses on doping ZnO with N [12], P [13], As [15] and Al-N [16] co-doped to achieve p-type conductivity. These dopants are used to alter the type of conductivity as well as the electrical and optical properties.…”

Nitrogen-doped ZnO nanorods prepared by hydrothermal diffusion

“…Group V elements have been shown to be the most promising dopants for producing p-type ZnO. According to earlier theoretical calculations of the electronic band structure, N is predicted to be the best candidate for producing a shallow acceptor level in ZnO [2], because the ionic radii of nitrogen and oxygen are comparable. Therefore, nitrogen atoms can replace oxygen with little lattice change.…”