Emission characteristics of self-assembled strained Ge_1−xSn_xislands for sources in the optical communication region

Abstract

Self-assembled strained Ge Sn islands on Si (100) have been grown at a low temperature using molecular beam epitaxy. The in-built strain and fraction of Sn in the islands have been estimated using x-ray photoelectron spectroscopy and high resolution x-ray diffraction study of grown samples. No-phonon assisted transition in the optical communication wavelength range of 1.4-1.8 μm has been observed in the Ge Sn island samples. The direct band gap transition intensity is found to increase with a growth in Sn concentration, with this increase in intensity sustained up to a temperature of 130 K in Ge Sn islands. The observed electroluminescence in p-i-n devices fabricated on Ge Sn island samples above a threshold bias of 4 V makes them attractive for future Si based optical devices.

Dislocation-related photoluminescence of GeSn films grown on Ge (001) substrates by molecular beam epitaxy

“…Thermal annealing, the most common technique for improving the crystal quality and the optical properties, will lead to a severe Sn segregation and the formation of Sn-rich precipitates for GeSn alloy as well as the formation of dislocations [13][14][15][16]. So the growth of high quality and efficient light-emitting GeSn materials by MBE is still a big challenge [17,18]. In addition, the PL properties of GeSn grown by MBE, including the knowledge about defect-related PL properties, are also important for comprehensively characterizing material microstructures and physical properties, and for completely understanding the correlation between material microstructure and physical property of GeSn materials.…”

Fabrication of ordered arrays of GeSn nanodots using anodic aluminum oxide as a template

“…With the nano-structured GeSn, the Sn content can easily reach over 10 at% as shown by our previous work and many other reports. 21,22,33) Such a high Sn content in our GeSn nanodots is obviously higher than the reported GeSn nanodots grown by Stranski-Krastanov growth mechanism on Si 34) and the GeSn nanodots array fabricated by Nanoheteroepitaxy technology. 35) Our Sn content is also comparable to the high 13% Sn content of the GeSn nanodots fabricated by MBE combined with nano-SiO 2 template.…”

Low-temperature formation of GeSn nanodots by Sn mediation

“…21) Some reports on the formation of GeSn QDs and NDs and theoretical studies have been made in recent years, [22][23][24][25] and electroluminescence (10 K) in the optical communication wavelength range has also been reported. 26) However, further progress is needed to realize light-emitting devices. Besides, from the viewpoint of crystal growth, GeSn and its nanostructures are attractive materials.…”