Abstract
Optical band gaps, , up to 0.5 eV higher than in single-crystal samples, are observed for chemically deposited films of CdSe and explained in terms of a quantum-size effect, whereby the electrons are localized in individual crystallites. The increase in depends strongly on deposition temperature, with the greatest increase obtained at the lowest temperature. Annealing at temperatures above the deposition temperature causes a decrease in ; this decrease is stronger at higher annealing temperature. Structural studies of the as-deposited layers showed them to be composed of microcrystalline, cubic CdSe, and electron microscopy resolved them into individual crystallites of typically 40–80-Å diameter, depending on deposition temperature. This is the first example reported of a three-dimensional quantum-size effect in a film.
- Received 27 January 1987
DOI:https://doi.org/10.1103/PhysRevB.36.4215
©1987 American Physical Society