Light emission from silicon-based structure has always been a huge challenge due to the indirect bandgap of the silicon material, which makes radiative recombination inefficient. While there are numerous demonstrations of photo-excited emission from silicon-based materials, it is far less common to show electrically-excited emission from silicon.

IME researchers have demonstrated an electrically-excited light emitting device from a silicon-based material. Details of this recent work have been published in Applied Physics Letters (Vol 90, 221103).

Light emission is facilitated through quantum confinement of the injected carriers within the nanoscale silicon structures. The picture, taken under dim light conditions, shows a square device lighted when an electrical bias is applied to it. The inset picture shows the same chip taken under lighted conditions before electrical bias. Tuning of the emission wavelength (color) has been demonstrated although the tuning range is small and is still limited within the orange color spectrum. Although the intensity of the emitted light is still too low for practical applications, this represents a major step in the pursuit of a silicon-based light source.

A square device is lighted when electrically biased. The inset shows the same die taken under lighted condition without biasing, showing the details of the die layout.