Controlled Growth of the Ordered Cadmium Sulfide Particulate Films and the Photoacoustics Investigation

• Published in: The journal of physical chemistry. B Vol. 101; no. 47; pp. 9703 - 9709
• Main Authors: Pan, Z. Y, Liu, X. J, Zhang, S. Y, Shen, G. J, Zhang, L. G, Lu, Z. H, Liu, J. Z
• Format: Journal Article
• Language: English
• Published: American Chemical Society 20.11.1997
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp9718212

Two kinds of cadmium sulfide (CdS) particulate films have been generated in situ by exposing stearic acid (SA) Langmuir monolayer at the air−aqueous CdCl2 interface to hydrogen sulfide (H2S) gas:  particulate films composed of oriented rodlike nanocrystals (A-type particulate films), and those of dotlike nanocrystals which formed a stripelike domain with straight edges aligned with 6-fold symmetry (B-type particulate films). The SA- coated CdS particulate films were transferred to a solid substrate and examined by transmission electron microscopy (TEM) and photoacoustic spectroscopy (PAS). The dark field image and the transmission electron diffraction of the TEM were used to study the morphology and growth mechanisms of the CdS particulate films in detail. The PAS of the CdS particulate films composed of the oriented rodlike nanocrystals shows a new peak at 417.5 nm. This peak implies some new physical phenomena corresponding to the ordered alignment of the semiconductor nanocrystals, which exists in the ordered nanosystems. The novel synthesis method described here leads to the fabrication of the highly oriented semiconductor quantum wires and provides a new method to investigate the structure of the Langmuir monolayer at the air−water interface.