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Effects of Annealing Temperature on Structural, Optical and Electrical Properties of Ge Nanocrystals Embedded in GeO x Matrix
Author(s) -
Rathore Mahendra Singh,
Vinod Arun,
Rao N. Srinivasa
Publication year - 2017
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201700024
Subject(s) - materials science , crystallinity , annealing (glass) , raman spectroscopy , amorphous solid , nanocrystal , analytical chemistry (journal) , band gap , spectroscopy , thin film , optoelectronics , crystallography , nanotechnology , optics , chemistry , composite material , physics , chromatography , quantum mechanics
In this paper, the effects of annealing temperature on the growth of Ge nanocrystals embedded in GeO x matrix have been investigated. GeO x thin films deposited on Si and quartz substrates using electron beam evaporation were annealed under nitrogen ambience at 650, 750 and 850 °C. The pristine and annealed samples have been characterized using X‐ray diffraction, Raman spectroscopy, Atomic force microscopy, UV‐Visible spectroscopy and Semiconductor Device Analyzer (SDA). It is evident from XRD that the as‐deposited films are amorphous in nature, whereas the annealed films upto 750°C reveal the coexistence of crystalline Ge and GeO 2 . However, a further increase in temperature reflects only GeO 2 phase and disappearance of Ge peak. The sharp and intense peak at 299 cm −1 for the films annealed up to 750 °C in the Raman spectra indicates the formation of Ge nanocrystals and the peak around 436 cm −1 is attributed to crystalline GeO 2 . The optical band gap of pristine and annealed films was calculated using UV–Vis spectroscopy. The I–V measurements of annealed films show the ohmic behavior. The results reveal that the annealing temperature significantly affects the crystallinity, size of nanocrystals and optical band gap of films. The impact of annealing temperature on the structural, optical and electrical properties of nc‐Ge embedded in GeO x matrix has been reported in detail.