Influence of air annealing on the structural, optical and electrical properties of chemically deposited CdSe nano-crystallites

Cadmium selenide nano-crystallites are grown onto amorphous glass substrate from an aqueous alkaline medium, using chemical bath deposition method at room temperature. The samples are annealed in air for 4 h at various temperatures and characterized by structural, optical and electrical properties. The as-deposited CdSe layers grew in the nanocrystalline cubic phase, with optical band gap, ‘Eg’ 2.3 eV and electrical resistivity of the order of 106 O cm. After annealing metastable nanocrystalline cubic phase transformed into stable polycrystalline hexagonal phase. Depending upon temperature, decease upto 0.6 eVand 103 O cm were observed in the Eg, and electrical resistivity, respectively. These changes have been attributed to the increase in the grain size of the CdSe crystallites. # 2003 Elsevier B.V. All rights reserved