Towards white light laser emission based on strained Poly:(Si/Ge)

Solubility of Sn in Ge has the most impact in the emission characteristics of direct band gap GeSn alloy. Here, we employed the metal induced crystallization (MIC) process of amorphous Ge and Si via Sn as a novel mechanism to incorporate Sn inside Ge and Si networks. (Al/Si/Sn/Ge/Sn) and (Al/Ge/Sn/Ge/Sn) multilayers are deposited by thermal vacuum evaporation on different substrates. The devices are annealed under low vacuum at 500 ºC. The Ge doped nanocrystals structure is investigated. The direct transition and band gap values have been estimated using diffuse reflectance spectroscopy and Photoluminescence (PL) measurements. PL indicted that the junctions have emissions from visible to NIR regions that make them promise in white light laser sources as well as waveguiding applications. Charge carrier lifetime and EL measurements show high lifetime and very sharp emission, respectively indicating that the prepared structure is a candidate for white laser diode applications.