Experimental Calibration of Sn‐Related Varshni Parameters for High Sn Content GeSn Layers
Résumé
From temperature‐dependent photoluminescence of a single Ge 0.84 Sn 0.16 sample, Sn‐related Varshni parameters are extracted and used as input parameters in an 8‐band k·p model, and predict direct bandgap energies of high Sn content GeSn alloys with concentration varying from 8% to 16%. Then, exhaustively compared are the calculated direct Γ‐valley bandgap energies to photoluminescence results of 13% and 16% Sn content alloys and to direct bandgap energies found in literature. The agreement between k·p modeling and experimental datasets is close to 3% for different strain conditions of GeSn epilayers. The outcome of this study is an 8‐band k·p model with a fixed set of parameters, the model being self‐sufficient to describe the direct bandgap of Ge 1− x Sn x layers with x varying from 8% to 16% for large ranges of strain and temperature.