Room temperature Photoluminescence of Bulk Ge and Ge_(1-x) Sn_x for Different Sn Concentration

Silicon (Si) integrated photonic devices have been the subject of much interest. However, the limitations of Si prevent it from being used as an efficient light source or detector. It has been shown that Ge with its indirect bandgap energy being close to the direct valley, can be band engineered to achieve optical gain by alloying it with Sn. However, the defect states that arise from the lattice mismatch between Ge and Sn can result in high dark current and low signal to noise ratio in detectors, as well as low gain in lasers. Currently, at AFRL, methods are being implemented to grow GeSn on Si with good crystal qualities. In this research, the optical properties of Ge and its alloys, GeSn are studied for different concentrations of Sn. The photoluminescence of bulk Ge and Ge_(1-x) Sn_x will be studied using a diffraction grating spectrometer and a 980nm pump laser. The results will show the benefits of the proposed growth techniques in producing high quality Ge_(1-x) Sn_x thin films that could lead to significant technological developments.https://ecommons.udayton.edu/stander_posters/3553/thumbnail.jp