Preparation and properties of ZnO and devices

Abstract

ZnO has gained interest in part because of its large exciton binding energy (60 meV), good for lasing with low threshold. The renewed interest in ZnO is fuelled by availability of high quality substrates, reports of p-type conductivity, and ferromagnetic behavior when doped with transitions metals. The field is also fuelled by theoretical predictions and perhaps experimental confirmation of ferromagnetism at room temperature for potential spintronics applications. Despite great strides there are still many challenges, the chief among them is the attainment of reproducibly low resistivity p-type ZnO. While ZnO already has many industrial applications owing to its piezoelectric properties and bandgap in the near UV, its applications to optoelectronic devices utilizing electrical injection has not yet been put to practice mainly due to the lack of p-type epitaxial layers. This review provides a discussion of some of the growth issues of ZnObased epitaxial and heteroepitaxial layers and their use in a variety of devices.

Synthesis of optical quality ZnO nanowires utilizing ultrasonic spray pyrolysis

“…A II-VI compound semiconductor, ZnO, is an environment-friendly material with a direct band gap of 3.37 eV at 300 K [1]. It has an exciton binding energy of 60 meV, which is considerably large compared with those of the other II-VI compounds such as CdS, CdSe, ZnSe, and ZnTe.…”

A Cadmium-Free Cu2ZnSnS4/ZnO Hetrojunction Solar Cell Prepared by Practicable Processes

“…The formation of a CZTS/ZnO hetrojunction was realized by depositing a ZnO layer on the CZTS film utilizing ultrasonic-spray pyrolysis (USP). 16) Using ZnO (the band gap: 3.37 eV at room temperature 17) ) as a buffer layer instead of CdS (the band gap: 2.42 eV at room temperature 18) ), an enhancement of light transmittance in the shorter wavelength regions was achieved. The deposition of the ZnO layer by the USP technique has advantages over chemical bath deposition (CBD) technique, since it is superior in obtaining a single phase high quality ZnO layer directly on a substrate without any post-annealing process: the former process is free from the formation of a hydroxyl phase such as Zn(OH) 2 that degrade the quality of ZnO.…”

Comparison of the synthesis routes for the ZnO/porous silica nanocomposite

“…In the present study, we focused on the semiconductor zinc oxide NPs. Nanocrystalline ZnO is one of the potential candidates for applications in optoelectronic devices [16], chemical gas sensors [17], solar cells [18], optical switches [19], as a catalyst [15], etc. Moreover, ZnO has been paid considerable attention as a promising electronic luminescent device material that enables producing light-emitting devices in the ultra-violet region.…”