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Microstructural and Optoelectronic Properties of SiGe:H Films at the Transition Edge Fabricated by PECVD
Author(s) -
Fan Shanshan,
Guo Qiang,
Wang Xinzhan,
Yu Wei,
Fu Guangsheng
Publication year - 2018
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201700141
Subject(s) - materials science , raman spectroscopy , plasma enhanced chemical vapor deposition , germanium , paracrystalline , photoconductivity , silicon , nanocrystalline silicon , grain boundary , optoelectronics , analytical chemistry (journal) , crystallography , crystalline silicon , microstructure , amorphous silicon , composite material , optics , chemistry , physics , chromatography
In this study, hydrogenated silicon–germanium (SiGe:H) films with different hydrogen dilution ratios (Ds) are fabricated by the PECVD technique, and the microstructural and optoelectronic properties of the films are studied using Raman, XRD, FTIR, and photo/dark conductivity spectra. It is shown that, with the increase of D, protocrystalline hydrogenated silicon–germanium (proto‐SiGe:H) appears just below the transition edge, characterized by low void density and high photosensitivity, and nanocrystalline hydrogenated silicon–germanium (nc‐SiGe:H) appears above the transition edge with a low interface phase and a high number of crystalline grains, presenting high photoconductivity. The paracrystalline structural model is used to elucidate the structural and electronic properties of proto‐SiGe:H films. In the Raman spectra, the paracrystalline fraction ƒ p , grain boundary fraction ƒ GB , and crystalline fraction ƒ c are the characteristic parameters of the protocrystalline and nanocrystalline SiGe:H films.