The Study Of High Speed And High Power Bi-polar Light-emitting Transistor For Optical Communications

In Optical fiber communication systems, LED has a mature technology, low-cost advantages that compared to other light sources,it couping with plastic optical fiber is to be able to meet the future short-distance optical fiber communication,such as The Internet of Things,which demand high-capacity, short-range, low-cost.The modulation speed of the LED is, however, limit on its carrier radiation recombination lifetime, and it usually only25MHz,but it is difficult to meet the demand for high-capacity transmission of the Internet of Things in the future.LET (light emitting transistor) which reported by the University of Illinois Feng has characteristics of transistors and LEDs, and it can overcome the inherent defects that the modulation speed of the LEDs is restricted to its carrier radiation recombination lifetime of traditional LEDs.In report, its modulation speeds can be up to4.3GHz. But,the luminous power of LET only in the level of microwatts which is difficult to meet the requirements of the light source in The Internet of Things.This thesis is based on the modulation speed and saturation optical power of LET, research and analysis on the working mechanism of the LET, and get the general law of the change of LET properties with the epitaxial layer parameters,.Then optimize the LET model based on this law and get the high-speed high-power Bi-polar light-emitting transistor that meet the Internet of Things.This work is based on simulation software APSYS used for semiconductor devices of Crosslight Software Inc, The main content of this paper includes three parts.(1) Verify the LET structure can be overcome the inherent that the modulation speed of the LEDs is restricted to its carrier radiation recombination lifetime of LEDs and study the relationship between the optical power&modulation speed and transistor common-emitter current gainβ.(2) Do the depth research and analysis on the parameter of base region and collector region how to affect the allocation of the electron and the hole which from base region and emitter region respectively, furthermore,how to influence the saturation optical power and modulation speed of LET, and get a general law for the change of LET performances with various parameter.(3) Then use the simulation results to further optimize the model, through balance the consumption mechanisms that consist of radiative recombination in base region and cross to the collector area of minority carriers, to make the light source which is to be able to meet the The Internet of Things that demand high-capacity, short-range, low-cost in the future become reality.