Photoluminescence characteristics of Er doped Ge nanocrystals embedded in alumina matrix

► Ge NCs with size varying from 4 to 7 nm were grown by pulsed laser deposition. ► Effect of Er concentration on 1.54 μm photoluminescence was investigated. ► Increase in photoluminescence intensity with Ge NC size was observed. ► Temperature dependent photoluminescence from Er doped Ge NCs was discussed.