Electroluminescence from MIS silicon-based light emitters with arrays of self-assembled Ge(Si) nanoislands

We report on the electroluminescence from silicon-based metal–insulator–semiconductor (MIS) diodes with arrays of self-assembled Ge(Si) nanoislands. Aluminum oxide (Al$_2$O$_3$) is used as an insulator material in the MIS contact. Variations in the electroluminescence spectra caused by changing the metal work function are examined. The intense electroluminescence from Ge(Si) nanoislands localized at a distance of 50 nm from the insulator–semiconductor interface is observed at room temperature. The emission spectrum is found to be controlled by choosing the design of the semiconductor structure and the barrier height for injected carriers.