Temperature dependent direct-bandgap light emission and optical gain of Ge
Liu Zhi, He Chao, Zhang Dongliang, Li Chuanbo, Xue Chunlai, Zuo Yuhua, Cheng Buwen
       

Maximum gain and net maximum gain of 0.25% tensile strained Ge films on Si with various n-doping at different temperatures. The input carrier concentration n = p = 1 × 1019 cm−3.