TY  - JOUR
AU  - von den Driesch, N.
AU  - Stange, D.
AU  - Wirths, S.
AU  - Mussler, G.
AU  - Holländer, B.
AU  - Ikonic, Z.
AU  - Hartmann, J. M.
AU  - Stoica, T.
AU  - Mantl, S.
AU  - Grützmacher, D.
AU  - Buca, D.
TI  - Direct Bandgap Group IV Epitaxy on Si for Laser Applications
JO  - Chemistry of materials
VL  - 27
IS  - 13
SN  - 1520-5002
CY  - Washington, DC
PB  - American Chemical Society
M1  - FZJ-2015-05063
SP  - 4693 - 4702
PY  - 2015
AB  - The recent observation of a fundamental direct bandgap for GeSn group IV alloys and the demonstration of low temperature lasing provide new perspectives on the fabrication of Si photonic circuits. This work addresses the progress in GeSn alloy epitaxy aiming at room temperature GeSn lasing. Chemical vapor deposition of direct bandgap GeSn alloys with a high Γ- to L-valley energy separation and large thicknesses for efficient optical mode confinement is presented and discussed. Up to 1 μm thick GeSn layers with Sn contents up to 14 at. % were grown on thick relaxed Ge buffers, using Ge2H6 and SnCl4 precursors. Strong strain relaxation (up to 81%) at 12.5 at. % Sn concentration, translating into an increased separation between Γ- and L-valleys of about 60 meV, have been obtained without crystalline structure degradation, as revealed by Rutherford backscattering spectroscopy/ion channeling and transmission electron microscopy. Room temperature reflectance and photoluminescence measurements were performed to probe the optical properties of these alloys. The emission/absorption limit of GeSn alloys can be extended up to 3.5 μm (0.35 eV), making those alloys ideal candidates for optoelectronics in the mid-infrared region. Theoretical net gain calculations indicate that large room temperature laser gains should be reachable even without additional doping.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000358104700023
DO  - DOI:10.1021/acs.chemmater.5b01327
UR  - https://juser.fz-juelich.de/record/202937
ER  -