Formation and photoluminescence of Ge and Si nanoparticles encapsulated inoxide layers

Ge and Si semiconductor nanoparticles encapsulated in oxide layers were pre pared by the inert gas condensation method. High-resolution electron micros copy and energy dispersive X-ray spectrometry showed the formation of the c ore-shell structures with a size below 10 nm. The optical absorption spectr a of Ge showed the band edges at higher energy compared to the ordinary Ge element. Photoluminescence measurements of them showed the luminescence at 2.2-2.6 eV, which would be due to the formation of core-shell structures. E specially, Ge clusters with a size of approximately 1 nm were formed in the GeOx matrix, which showed strong luminescence at 3.12 eV, which would be d ue to the quantum size effect of the clusters. The present work indicates t hat formation of the core-shell structure of semiconductor nanoparticles wi th oxide layers would be effective for blue shifts of the energy band. 2000 Elsevier Science S.A. All rights reserved.