Germanium nanocrystals (NCs) embedded in Silica matrix were produced by using atom beam sputtering (ABS). The as-deposited films were subjected to rapid thermal annealing at various temperatures under N₂ atmosphere. The average size of NCs in the sample was estimated using X-ray diffraction (XRD), and high resolution transmission electron microscopy (HRTEM). XRD reveals that as deposited films show amorphous nature whereas annealed samples show crystalline nature. The Raman peak was found to shift from its bulk value, indicating phonon confinement of nanocrystals. Rutherford back scattering spectrometry (RBS) was used to quantify the concentration of Ge in the SiO₂ matrix. Variation of crystallite size with annealing temperature has been explained and a detailed discussion of results will be given.

N Srinivasa Rao, School of Physics, University of Hyderabad, India
Anand P Pathak*, School of Physics, University of Hyderabad, India
N Sathish, School of Physics, University of Hyderabad, India
G Devaraju, School of Physics, University of Hyderabad, India
V Saikiran, School of Physics, University of Hyderabad, 
G Sai Saravanan, 3Gallium Arsenide Enabling Technology Centre, Hyderabad, India
D K Avasthi, Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067, 
D Kabiraj, 2Inter University Accelerator Centre, New Delhi, 

*presenting author