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FIZIKA A 11 (2002) 2 , 61-72
 
PHYSICAL PROPERTIES OF NANOPARTICLE SILICA GEL DOPED WITH CdS PREPARED
BY SOL-GEL TECHNIQUE
I. K. BATTISHA
Solid State Physics Department, National Research Center, Cairo, Egypt
Received 26 October 2000; revised manuscript received 15 October 2001
Accepted 7 February 2002 Online 25 May 2002
CdS/silica xerogel glasses were prepared via silica gels containing mixture solution of
0.2 M (CdCl2 and thiourea) with molar ratio 1:1. Doping the gels with this
mixture solution and its heat treatment gave transparent yellow silica-gel glasses doped
with CdS crystals. X-ray diffraction and transmission electron microscope make it possible
to evaluate the nanoparticle size of the prepared samples. The nanoparticle size was
dependent on the concentration of the dopant materials and the heating temperature. In the
optical transmission spectra, the absorption edge exhibited a blue shift compared to that
of the bulk CdS, and its energy shift was reciprocally proportional to the square of the
radius. Thus the quantum-size effect could be found for the silica gel containing CdS
prepared by the sol-gel process. The energy band gap shifted to higher energy for smaller
nanoparticle size.
PACS numbers: 81.20.Ka, 82.70.Gg
UDC 538.911, 538.958
Keywords: CdS/silica xerogel, doping with CdCl2:thiourea mixture solution,
XRD, TEM, TGA, DTA, FTIR investigations, nanoparticles, band gap energy
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