Comparative Study of Synthesis of CdO-ZnO Nanocomposite Thin Films by Different Methods: A Review

Abstract

II-VI semiconductors, owing to the availability of a large variety of techniques to prepare it, the large number of structures and nanostructures in which it can be condensed, as well as the large and varied number of industrial applications [13]. ZnO has a wurtzite structure in which the oxygen atoms are arranged in a hexagonal-close-packed lattice with zinc atoms occupying half the tetrahedral sites. This is a very well known semiconductor with a wide band gap in the near ultraviolet of ~ 3.37 eV at room temperature [14]. Cadmium oxide (CdO) is also a well-known II-VI n-type semiconductor that has interesting properties for optoelectronic applications due to its large band gap, low electrical resistivity and high optical transmittance in the visible region of the solar spectrum [15]. It can be found in various types of nano structures with a variety of properties and applications such as UV and visible photoluminescence, photo catalysts and field emission, ambient temperature ferromagnetism and high electronic mobility [16] as well as photo detectors, solar cells, piezoelectric devices [17]. It has been well studied as a sensor material to detect most of the reducing gases [18]. CdO has a rock salt crystal structure with a direct band gap of 2.2 eV to 2.5 eV and indirect band gap of 1.98 eV, which makes it useful for a wide range of applications such as solar cells, photodiodes, and transparent electrodes and sensors [19][20][21][22] [29]. In the present work we have done a comparative study of transports properties of ZnO-CdO thin films synthesis by sol-gel, magnetron sputtering and spray pyrolisis techniques.

The Influence of the Growth Temperature on the Structural Properties of {CdO/ZnO}30 Superlattices

“…Several techniques were tried to deposit Zn x –1 Cd x O layers, including pulsed laser sputtering, molecular beam epitaxy (MBE), a dc reactive magnetron sputtering method, spray pyrolysis technique, , and others. Obviously, the growth method has an impact on the Cd content, structural and optoelectronic characteristics of the obtained ternary alloy. , However, the quality of the films prepared by many methods was unsatisfactory due to the coexistence of multiphase and polycrystalline states . The structure of wurtzite is the most stable for ZnO and therefore the most common, while CdO has a cubic-type structure. , Also, the difference in crystal structures limits the Cd solubility in ZnO .…”

“…Obviously, the growth method has an impact on the Cd content, structural and optoelectronic characteristics of the obtained ternary alloy. 22,23 However, the quality of the films prepared by many methods was unsatisfactory due to the coexistence of multiphase and polycrystalline states. 24 The structure of wurtzite is the most stable for ZnO and therefore the most common, while CdO has a cubic-type structure.…”