IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Nanometer Structures Thursday Sessions
       Session NS-ThP

Paper NS-ThP7
CdS Self-assambled Nanostructures Produced by Pulsed Laser Deposition@footnote 1@

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Poster Session
Presenter: M. Meléndez-Lira, Cinvestav-IPN, México
Authors: C. Manzano, Cinvestav-IPN, México
R. Castro, Cinvestav-IPN, México
J.L. Peña, CICATA-IPN, México
M.A. Santana-Aranda, Cinvestav-IPN, México
M. Meléndez-Lira, Cinvestav-IPN, México
Correspondent: Click to Email
Low-dimensional structures are very attractive due to their potential application in the production of high-efficiency opto-electronic devices. Until now, most of the semiconductor self-assembled nanostructures (SSN) have been fabricated employing epitaxial deposition techniques. The formation mechanism of SSN has been identified as the misfit strain involved during the heteroepitaxial growth. We report results of the production, and optical and structural characterization of CdS nanostructures deposited by pulsed laser deposition on Corning glass substrates (CGS), two possible mechanisms for the production of these nanostructures are discussed: 1) stress due to differences in the thermal expansion coefficients of the CdS film and CGS; 2) CdS droplets ejected from the target and directly deposited on the CGS. The samples were grown using a Nd:YAG laser focused on a rotating CdS target. Depositions were performed with 50 lasers shots employing substrate temperatures of 250, 350 and 500°C under a pressure of 10@super -6@ Torr. The morphology of the deposited CdS layers was examinated by atomic force microscopy finding the presence of elliptic islands with typical dimensions around 60 and 30 nm for the major and minor axis lengths, respectively. There is no evidence of degradation with time or handling. A clear blue shift, with values up to 100 meV, of the absorption band edge was observed in the room temperature transmission spectroscopy (TS) measurements, and was attributed to quantum confinement. Room temperature modulated transmission spectroscopy (MTS) measurements indicated a blue shift of only 7 meV. The differences between the results from TS and MTS are discussed taking in account the islands size distribution. These results are correlated with those obtained from 10 K photoluminescence, x-ray diffraction and scanning electron microscopy measurements. @FootnoteText@ @footnote 1@ Work partially supported by CONACyT-México.