Temperature-Driven Structural and Morphological Evolution of Zinc Oxide Nano-Coalesced Microstructures and Its Defect-Related Photoluminescence Properties

Abstract

In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide. The temperature-driven morphological evolution of the zinc oxide nano-coalesced microstructures was perceived, resulting in transformation of quasi-mountain chain-like to pyramidal textured zinc oxide with increasing the synthesis temperature. The results also impart that the sample prepared at 500 °C shows a higher percentage of the zinc interstitial and oxygen vacancies. Furthermore, the intensity of the photoluminescence emission in the ultraviolet region was enhanced as the heating temperature increased from 500 °C to 700 °C. Lastly, the growth mechanism of the zinc oxide nano-coalesced microstructures is discussed according to the reaction conditions.

ZnO films using a precursor solution irradiated with an electron beam as the cathode interfacial layer in inverted polymer solar cells

“…It is known that the relative content of donor and acceptors inuences the semiconductor properties of ZnO. 25 Scheme 1 and Table 1 show the various defects level emissions for the deconvoluted peaks (a to f) of the PL spectra (Fig. 3c).…”

“…The violet emission (peak b) displayed in all the samples is probably attributed to (1) Zn i (about 0.22 eV below the CB) / VB transition or (2) CB / single ionized V Zn (about 0.3 eV above the VB) or (3) CB / O i (about 0.4 eV above the VB). [25][26][27] The blue emission (peak c) of EB-Z300 and EB-Z500 is due to ex-Zn i , which is the extended states of Zn i from 0.54 to 0.64 eV below the CB. 26,27 This can be correlated to the additional Zn 1p peaks of EB-Z300 and EB-Z500 (the shaded area, inset Fig.…”

Ultraviolet Sensors Based on Two-Dimensional Zinc Oxide Structures

“…Moreover, ZnO can be synthesised through different processes, and films were grown on different low-cost substrates, such as ordinary papers [18], polymers [19,20], slide glasses [15], and silicon wafers [10]. Furthermore, high-quality ZnO can be prepared using simple methods with repeatable characteristics, including methods such as radio frequency (RF) magnetron sputtering [21], low temperature hydrothermal processes [22,23], thermal evaporation [24,25], sol-gel [26], electrodeposition [27], and chemical vapour deposition (CVD) [28]. Another advantage of ZnO is that it is easily synthesised into different structures in the nanoscale range (nanostructures).…”

Mechanisms behind slow photoresponse character of Pulsed Electron Deposited ZnO thin films

“…On the other hand, zinc related defects such as; zinc interstitials (neutral, single and double ionized) are responsible for blue emission. According to the previous reports [29][30][31][32][33][34], the observed emissions in PL spectrum ( Fig. 3(a)) can be summarized as follows: the Now we turn to time-dependent photo-response measurements.…”