Annealing effect on optical properties of ZnO films fabricated by cathodic electrodeposition

Wang, Qingtao; Wang, Guanzhong; Jie, Jiansheng; Han, Xinhai; Xu, Bo; Hou, J. G.

doi:10.1016/j.tsf.2005.06.046

Cited by 54 publications

(24 citation statements)

References 27 publications

(31 reference statements)

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“…This is a result of the Zn(OH) 2 decomposition to ZnO, consistent with part b of Figure 2A and with previous findings [30,37,38]. On the other hand, from 200°C to 300°C, the intensity increases (part c of Figure 2B) indicating an increase in point defect concentration.…”

Section: Resultssupporting

confidence: 92%

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Tuning of defects in ZnO nanorod arrays used in bulk heterojunction solar cells

et al. 2012

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With particular focus on bulk heterojunction solar cells incorporating ZnO nanorods, we study how different annealing environments (air or Zn environment) and temperatures impact on the photoluminescence response. Our work gives new insight into the complex defect landscape in ZnO, and it also shows how the different defect types can be manipulated. We have determined the emission wavelengths for the two main defects which make up the visible band, the oxygen vacancy emission wavelength at approximately 530 nm and the zinc vacancy emission wavelength at approximately 630 nm. The precise nature of the defect landscape in the bulk of the nanorods is found to be unimportant to photovoltaic cell performance although the surface structure is more critical. Annealing of the nanorods is optimum at 300°C as this is a sufficiently high temperature to decompose Zn(OH)2 formed at the surface of the nanorods during electrodeposition and sufficiently low to prevent ITO degradation.

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Section: Resultssupporting

confidence: 92%

“…This has been attributed previously to signal quenching from a Zn(OH) 2 layer present on the as-deposited ZnO [30,37,38]. Indeed, the presence of OH peaks in the IR spectra at ca.…”

Section: Resultssupporting

confidence: 53%

Tuning of defects in ZnO nanorod arrays used in bulk heterojunction solar cells

et al. 2012

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“…Different rates correspond to a mixture of the wurtzite structure with some collateral products, 13 or other crystalline structures 14,15 that are not suitable for optoelectronic applications. 16 It can be concluded also that the pulsed current electrodeposition allows a good control of the ZnO nucleation step, leading to a more pure wurtzite nanostructure. If the transmission spectrum is analyzed, the magnitude and position of the transmission jump provides a good assessment on the optical quality of the film determining in fact the optimum conditions for its application in hybrid solar cells.…”

Section: Results Analysismentioning

confidence: 97%

ZnO Nanoestructured Layers Processing with Morphology Control by Pulsed Electrodeposition

Tolosa¹,

Orozco-Messana²,

Damonte³

et al. 2011

J. Electrochem. Soc.

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The fabrication of nanostructured ZnO thin films is a critic process for a lot of applications of this semiconductor material. The final properties of this film depend fundamentally of the morphology of the sintered layer. In this paper a process is presented for the fabrication of ZnO nanostructured layers with morphology control by pulsed electrodeposition over ITO. Process optimization is achieved by pulsed electrodeposition and results are assessed after a careful characterization of both morphology and electrical properties. SEM is used for nucleation analysis on pulsed deposited samples. Optical properties like transmission spectra and Indirect Optical Band Gap are used to evaluate the quality of the obtained ZnO structures. Solar cell devices with industrial application are stratified laminar materials, with several dm 2 of exposed surface, processed by piling up several layers with different composition, each of them has a different function and complementary in the device. The performance of present commercial solar cells (that are based in semiconductors III-V, with Si poly or mono crystalline) is determined by the different fabrication process.1,2 In all of them, the production of diverse interfaces is the design factor, developed by growing different layers. The final properties of the semiconductor are defined by the type of boundary, the chemical species present, etc. . .. One of the determining factors in the final performance of the cell is its morphology, and the final product quality depends on the possibility of having a close control on the nucleation parameters.3,4 The optimization of these interfaces is a challenge for the photovoltaic industry, optimization must be based on a thorough understanding on the growth mechanisms. Likewise, the key for a successful implementation of photovoltaic energy is based on how industry attains a cheaper and more efficient process for cell fabrication. It is therefore necessary to reduce costs and production time of the cells without decreasing its performance. This requires more efficient production processes. These goals are common to all manufacturers of photovoltaic cells. Given the above scenario electrodeposition is selected as a favoured technique. This study develops the manufacture of inorganic layers of nanostructured ZnO for photovoltaic applications trough low-cost technology. In particular, Pulsed current electrodeposition (ED) is to be presented as a highly promising alternative. The aim of this study is to analyze the influence of waveform control for the electrodeposition current on the morphology as a tool to control the optical properties of the thin layer. The selected material (ZnO) has a mesoporous nanocrystalline structure optimal for the development of hybrid solar cells. These materials have been characterized using different techniques to quantify the ability of the photovoltaic material, and at the same time, to correlate morphology and optoelectronic properties. In particular, the optical, electrical and structural best suited fo...

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“…7. The indirect energy band gap (E g ) was estimated by extrapolating the linear part of the (ahy) 1/2 curve to the energy axis, where a is the absorption coefficient; a ¼ ln (1/T) [28], where T is approximately 1-Absorbance, as shown in Fig. 8.…”

Section: Resultsmentioning

confidence: 99%