Microstructural and Optoelectronic Properties of SiGe:H Films at the Transition Edge Fabricated by PECVD. Issue 9 (19th July 2018)

• Record Type: Journal Article
• Authors: Fan, Shanshan; Guo, Qiang; Wang, Xinzhan; Yu, Wei; Fu, Guangsheng
• Is Part Of: Crystal research and technology. Volume 53:Issue 9(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-07-19
• Subjects: characteristic parameter -- hydrogen dilution ratios -- nanocrystalline hydrogenated silicon–germanium -- photosensitivity -- protocrystalline hydrogenated silicon–germanium; Crystallography -- Periodicals; 548
• DOI: 10.1002/crat.201700141
• Languages: English
• ISSNs: 0232-1300

Abstract

Abstract: 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 ƒp, grain boundary fraction ƒGB, and crystalline fraction ƒc are the characteristic parameters of the protocrystalline and nanocrystalline SiGe:H films. Abstract : The transition from amorphous to microcrystalline takes place with increase of hydrogen dilution. It has been shown that the regimes below and above this transition edge are suitable for making high‐efficiency solar cells. In this article, the paracrystalline structural model is used to elucidate the structural and electronic properties of films below transition edge. The characteristic parameters are found for films below and above transition edge from Raman spectra. .