Sol–Gel Synthesis of Cadmium Telluride‐Microcrystal‐Doped Silica Glasses

The sol–gel process has been applied to the preparation of small‐sized CdTe‐doped silica glasses. Gels synthesized by the hydrolysis of a complex solution of Si(OC 2 H 5 ) 4 , Cd(CH 3 COO) 2 · 2H 2 O, and Te were heated from 350° to 600°C in a H 2 ─N 2 atmosphere to form fine cubic CdTe crystals. The size of CdTe crystals, determined from the line broadening of X‐ray diffraction pattern, increases from 4 to 9 nm in diameter with increasing heat‐treatment temperature. The optical absorption edge shifts to the higher‐energy side as the size of the CdTe crystals decreases. This phenomenon is interpreted in terms of a quantum confinement effect of electron and hole in the CdTe microcrystals.