Small-Signal Circuit Model Analysis and Characterization of Resonant-Cavity Light-Emitting Transistors
Date Issued
2014
Date
2014
Author(s)
Huang, Yin-Jie
Abstract
The invention of light-emitting transistors (LETs) in 2004 has revolutionized the concept of the carrier radiative recombination rate for the past 50 years. It is recognized that the radiative recombination lifetime of the light-emitting diodes (LEDs) and diode lasers (DLs) are in the nano-second range. However, the pico-second level of recombination lifetime of LETs and transistor lasers (TLs), which can be determined by experiments, provides great potential for next generation optical communication light source.
In order to model the microwave optical response of LETs, to under the small-signal circuit model and their electrical transfer functions are important. In this thesis, we calculate the electrical transfer function in different configurations, such as common-emitter, common-base, and common-collector. We assume the optical emission in light-emitting transistors is dominated by base-emitter junction as the optical emission in light-emitting diodes under forward bias. We calculate the effect of the input impedance and obtain an electrical transfer function from input terminal to base-emitter junction. The simulation results agree well with our experimental data in different configurations and different microwave inputs.
Moreover, we investigate resonant-cavity light emitting transistors (RCLETs) with additional high reflection mirrors. The base layer, which is the active layer, includes two undoped In0.2Ga0.8As quantum wells to enhance the base radiative recombination. With 35 pairs of bottom Al0.12Ga0.88As/Al0.9Ga0.1As Distributed Bragg Reflector (DBR) and 3 pairs of top DBR sandwiching LET structure, the spontaneous emission can be enhanced by the resonant-cavity. The full width at half maximum (FWHM) of emission peak of a RCLET is 21 nm at 980 nm while that of a conventional LET is about 96 nm. Then the RCLET is deposited by 16 pairs of TiO2/SiO2 external high reflection mirrors on the top. By doing this, the FWHM can be further reduced to 5 nm.
The last part of this thesis, we try to fabricate and characterize vertical cavity surface emitting lasers (VCSELs). The emission wavelength of the VCSEL is 850nm. We investigate the influence of aperture size on the modulation speed of VCSEL.
Subjects
小訊號模型
轉換函數
共振腔發光電晶體
垂直共振腔面射型雷射
Type
thesis
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