The Intersubband Approach to Si-based Lasers

摘要: Silicon has been the miracle material for electronics industry, and past twenty years, technology based on Si microelectronics engine driving digital revolution. For rapid “Moore’s Law” miniaturization of device sizes yielded an ever-increasing density fast components integrated chips: but during time that feature size was pushed down towards its ultimate physical limits, there also a tremendous effort to broaden reach by expanding functionalities well beyond electronics. is now being increasingly investigated as platform building photonic devices. The field photonics seen impressive growth since early visions in 1980s 1990s [1,2]. huge infrastructure global industry expected benefit fabrication highly sophisticated devices at costs are lower than those currently required compound semiconductors. Furthermore, Si-based make possible monolithic integration with high speed electronics, thereby enabling oncoming “optoelectronic revolution”. Among many up complete set necessary including light emitters, amplifiers, photodetectors, waveguides, modulators, couplers switches, most difficult challenge lack efficient source. reason this striking absence bulk indirect band gap where minimum conduction maximum valence do not occur same value crystal momentum wave vector space (Fig. 1). Since photons have negligible compared electrons, recombination electron-hole pair will be able emit photon without simultaneous emission or absorption phonon order conserve momentum. Such radiative second-order effect occurring small probability, which competes nonradiative processes take place much faster rates. As result, marvelous it choice making emitting lasers. Nevertheless, driven enormous payoff advancement commercialization, research groups around world seeking novel approaches overcome intrinsic problem develop sources Si. One interesting method use nanocrystals dispersed dielectric matrix, often times SiO2. nano-scaled clusters naturally formed thermal annealing Si-rich oxide thin film. situated wider SiO2 can effectively localize electrons quantum confinement, improves shifts spectrum toward shorter wavelengths,