Self-Assembled, Stabilizer-Free ZnS Nanodot Films Using Spray-Based Approaches

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• 作者：Yanpeng Fu ; Rodrigo S谩ez-Araoz ; Tristan Koehler ; Martin Krueger ; Daniel Abou-Ras ; Alexander Steigert ; Iver Lauermann ; Ulrike Bloeck ; Martha Ch. Lux-Steiner ; Christian-H. Fischer
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：November 21, 2013
• 年：2013
• 卷：117
• 期：46
• 页码：24632-24639
• 全文大小：511K
• 年卷期：v.117,no.46(November 21, 2013)
• ISSN：1932-7455

文摘

A direct self-assembly of high-quality, uncoated ZnS nanodots on a given substrate was obtained using two techniques: the sequential and cyclic spray ion layer gas reaction (spray-ILGAR) as well as the simultaneous and continuous spray chemical vapor deposition (spray-CVD). The spray-ILGAR nanodots are homogeneous in size (3鈥? nm), regular in shape, and uniform in composition, while the spray-CVD nanodots are larger and irregular in shape with inclusions of ZnO. By employing these two spray-based techniques, the synthesis of nanodots directly assembled on the substrate surface can be realized in a controlled manner, covering a certain range of compositions, tunable sizes, and controllable interparticle distances. In situ mass spectrometry was implemented in the real-time process in order to achieve better understanding of the intrinsic chemistry involved. We systematically study the influence of the process parameters on the formation of the nanodots and compare the morphology, composition, and property of the obtained nanodots. Based on these investigations, the underlying mechanism that controls the special growth of the nanodots in spray-ILGAR and spray-CVD processes is proposed. It can account for the similarities and differences of these two kinds of nanodots. A passivation/point contact bilayer, composed of the spray-based ZnS nanodots covered by a homogeneous ILGAR In₂S₃ layer, is used as the buffer in the chalcopyrite solar cells, resulting in the cell performance improvement compared to the pure ILGAR In₂S₃ buffer.