The Interplay between Strain, Sn Content, and Temperature on Spatially Dependent Bandgap in Ge1−xSnxMicrodisks

physica status solidi (RRL) - Rapid Research Letters, vol. 18

Abstract

Germanium–tin (GeSn) microdisks are promising structures for complementary metal–oxide–semiconductor‐compatible lasing. Their emission properties depend on Sn concentration, strain, and operating temperature. Critically, the band structure of the alloy varies along the disk due to different lattice deformations associated with mechanical constraints. An experimental and numerical study of Ge1−xSnxmicrodisk with Sn concentration between 8.5 and 14 at% is reported. Combining finite element method calculations, micro‐Raman and X‐ray diffraction spectroscopy enables a comprehensive understanding of mechanical deformation, where computational predictions are experimentally validated, leading to a robust model and insight into the strain landscape. Through micro‐photoluminescence experiments, the temperature dependence of the bandgap of Ge1−xSnxis parametrized using the Varshni formula with respect to strain and Sn content. These results are the input for spatially dependent band structure calculations based on deformation potential theory. It is observed that Sn content and temperature have comparable effects on the bandgap, yielding a decrease of more than 20 meV for an increase of 1 at% or 100 K, respectively. The impact of the strain gradient is also analyzed. These findings correlate structural properties to emission wavelength and spectral width of microdisk lasers, thus demonstrating the importance of material‐related consideration on the design of optoelectronic microstructures.

Authors 10

1. Ignatii Zaitsev

   Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP–Leibniz-Institut für Innovative Mikroelektronik Im Technologiepark 25 15236 Frankfurt (Oder) Germany

2. Agnieszka Anna Corley‐Wiciak Aachen

   RWTH Aachen University · Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP–Leibniz-Institut für Innovative Mikroelektronik Im Technologiepark 25 15236 Frankfurt (Oder) Germany

   RWTH Aachen University Templergraben 55 52062 Aachen Germany

3. Cedric Xavier Corley-Wiciak

   Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP–Leibniz-Institut für Innovative Mikroelektronik Im Technologiepark 25 15236 Frankfurt (Oder) Germany

4. Marvin Hartwig Zoellner

   Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP–Leibniz-Institut für Innovative Mikroelektronik Im Technologiepark 25 15236 Frankfurt (Oder) Germany

5. Carsten Richter

   Leibniz Institute for Crystal Growth

   Affiliation as printed

   IKZ – Leibniz -Institut für Kristallzüchtung Max-Born-Straße 2 D-12489 Berlin Germany

6. Edoardo M. Zatterin

   European Synchrotron Radiation Facility

   Affiliation as printed

   ESRF – European Synchrotron Radiation Facility 71, avenue des Martyrs, CS 40220 38043 Grenoble Cedex 9 France

7. Michele Virgilio

   University of Pisa

   Affiliation as printed

   Dipartimento di Fisica “Enrico Fermi” Università di Pisa Largo Bruno Pontecorvo 3 56127 Pisa Italy

8. Beatriz Martín‐García

   Ikerbasque · CIC nanoGUNE

   Affiliation as printed

   CIC nanoGUNE BRTA Tolosa Hiribidea 76, Basque Country 20018 Donostia-San Sebastián Spain

   IKERBASQUE, Basque Foundation for Science Basque Country 48009 Bilbao Spain

9. Davide Spirito

   Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP–Leibniz-Institut für Innovative Mikroelektronik Im Technologiepark 25 15236 Frankfurt (Oder) Germany

10. Costanza Lucia Manganelli corresponding

    Leibniz Institute for High Performance Microelectronics

    Affiliation as printed

    IHP–Leibniz-Institut für Innovative Mikroelektronik Im Technologiepark 25 15236 Frankfurt (Oder) Germany