TY - JOUR

T1 - On the Formation of IR-Light-Emitting Ge Nanocrystals in Ge

T2 - SiO2 Films

AU - Volodin, V. A.

AU - Rui, Zhang

AU - Krivyakin, G. K.

AU - Antonenko, A. Kh

AU - Stoffel, M.

AU - Rinnert, H.

AU - Vergnat, M.

PY - 2018/9/1

Y1 - 2018/9/1

N2 - Abstract: The study is concerned with light-emitting Ge nanocrystals formed during the annealing of Gex[SiO2]1 – x films produced by the high-vacuum cosputtering of germanium and quartz targets onto substrates at a temperature of 100°C. In accordance with the conditions of growth, the Ge molar fraction was varied from 10 to 40%. By means of electron microscopy and Raman spectroscopy, amorphous Ge nanoclusters ~4–5 nm in dimensions are detected in as-deposited films with a Ge content higher than 20 mol %. To crystallize amorphous nanoclusters, annealing at temperatures of up to 650°C is used. The kinetics of the crystallization of Ge nanoclusters is studied, and it is established that up to ~1/3 of the amorphous phase is retained in the system, supposedly at the interfaces between nanocrystals and the surrounding amorphous SiO2 matrix. It is found that, upon annealing in normal atmosphere, germanium nanoclusters are partially or completely oxidized (at a Ge molar fraction of 30% and smaller). An intense infrared photoluminescence signal from quantum-confined Ge nanocrystals and a visible photoluminescence signal defined by defect complexes (oxygen vacancy + excess Ge atoms) are observed.

AB - Abstract: The study is concerned with light-emitting Ge nanocrystals formed during the annealing of Gex[SiO2]1 – x films produced by the high-vacuum cosputtering of germanium and quartz targets onto substrates at a temperature of 100°C. In accordance with the conditions of growth, the Ge molar fraction was varied from 10 to 40%. By means of electron microscopy and Raman spectroscopy, amorphous Ge nanoclusters ~4–5 nm in dimensions are detected in as-deposited films with a Ge content higher than 20 mol %. To crystallize amorphous nanoclusters, annealing at temperatures of up to 650°C is used. The kinetics of the crystallization of Ge nanoclusters is studied, and it is established that up to ~1/3 of the amorphous phase is retained in the system, supposedly at the interfaces between nanocrystals and the surrounding amorphous SiO2 matrix. It is found that, upon annealing in normal atmosphere, germanium nanoclusters are partially or completely oxidized (at a Ge molar fraction of 30% and smaller). An intense infrared photoluminescence signal from quantum-confined Ge nanocrystals and a visible photoluminescence signal defined by defect complexes (oxygen vacancy + excess Ge atoms) are observed.

KW - OPTICAL-PROPERTIES

KW - INFRARED PHOTOLUMINESCENCE

KW - QUANTUM CONFINEMENT

KW - SI

KW - NANOSTRUCTURES

KW - ABSORPTION

KW - MODE

UR - http://www.scopus.com/inward/record.url?scp=85052126636&partnerID=8YFLogxK

U2 - 10.1134/S1063782618090233

DO - 10.1134/S1063782618090233

M3 - Article

AN - SCOPUS:85052126636

VL - 52

SP - 1178

EP - 1187

JO - Semiconductors

JF - Semiconductors

SN - 1063-7826

IS - 9

ER -