Photoluminescence of strained germanium microbridges at various temperatures: experiment and modeling

The results of the experimental study and theoretical simulation of the photoluminescence (PL) spectra of strained germanium microbridges with improved heat sink are reported. It was shown that in the structures under study the main contribution to the PL signal of micro-bridges is provided by the radiative transitions from $\Gamma$-valley to the valence band in the whole considered temperature range (from 80 to 300 K). The influence of interference and self-absorption effects on the shape of the PL spectra of Ge microbridges is discussed. It was demonstrated that Ge microbridges with improved heat sink which was achieved due to the adhesion of the bridges to the underlying layers due to capillary forces are not subjected to the additional stretching as the temperature decreases in contrast to the suspended ones.