Electroluminescence from Ge on Si substrate at room temperature

A Ge/Si heterojunction light emitting diode with a p+-Ge/i-Ge/N+–Si structure was fabricated using the ultrahigh vacuum chemical vapor deposition technology on N+–Si substrate. The device had a good I-V rectifying behavior. Under forward bias voltage ranging from 1.1 to 2.5 V, electroluminescence around 1565 nm was observed at room temperature. The mechanism of the light emission is discussed by the radiative lifetime and the scattering rate. The results indicate that germanium is a potential candidate for silicon-based light source material.