Traditional semiconductor light emitting diodes (LEDs) have low modulation speed because of long spontaneous emission lifetime. Spontaneous emission in semiconductors (and indeed most light emitters) is an inherently slow process owing to the size mismatch between the dipole length of the optical dipole oscillators responsible for light emission and the wavelength of the emitted light. More simply stated: semiconductors behave as a poor antenna for its own light emission. By coupling a semiconductor at the nanoscale to an external antenna, the spontaneous emission rate can be dramatically increased alluding to the exciting possibility of an LED that can be directly modulated faster than the laser. In this project, we plan to demonstrate an antenna- enhanced nanoscale semiconductor light emitting diode (nanoLED) with direct modulation rate 50 GHz, exceeding the bandwidth of the semiconductor laser. Such an nanoLED is well-suited as a light source for on-chip optical communication where small size, fast speed, and high efficiency are needed to achieve the promised benefit of reduced power consumption of on-chip optical interconnect links compared with less efficient electrical interconnect links.
Project end date: 08/12/19