An Efficient Forward-Biased Si CMOS LED With High Optical Power Density and Nonlinear Optical-Power-Current Characteristic

A forward-biased silicon-based light-emitting device (Si-LED) was designed and fabricated by standard 0.18 μm complementary metal-oxide-semiconductor (CMOS) technology without any modification. For the Si-LED, wedge-shaped electrodes and needle-like tip were designed to enhance the intensity of electric field. When the Si-LED works at high forward current, the output optical power increases rapidly with the increase of forward current, which is a non-linear growth similar to exponential. To the best of our knowledge, such a phenomenon has never been reported before. Moreover, when the forward current is at 200 mA, the optical power density reaches 32.7 nW·μm
²
, which is two or three orders higher than that of other ever reported forward-biased Si-LED fabricated by standard CMOS technology. In addition, the red shift of the main peak in the spectra of Si-LED was observed and analyzed, and also the light-emission mechanism of each peak in the spectra was given.