A Study Of GeSn Light-emitting Diode

To further improve the performance of the device, new material,Ge Sn, comes into research field,the band gap of Ge Sn can continuously varied, i.e.the indirect band gap semiconductor can be changed into the direct band gap semiconductor, and because the lattice constant of Sn is larger than that of Ge, thus when forming Ge Sn alloys, Ge will generate a tensile strain, and the migration rate of the material will increase exponentially respecting to the conventional semiconductor, therefore the Ge Sn material has a very broad application prospects in the photovoltaic device.In the photovoltaic devices, the Ge Sn material can extend the spectral range from visible light to infrared light even to far-infrared light, and can enhance the emission intensity of LED and other devices, at the same time, Ge Sn material can be also used as conductive channel in the field-effect transistor or the like, taking advantage of its higher carrier mobility can greatly enhance the electrical characteristics of the device.However, Ge Sn material is more difficult to obtain, mainly because of the lattice mismatch, lower solubility and surface segregation of Sn and Ge, the quality of Ge Sn material directly determines the performance of the device, therefore how to get better quality of Ge Sn alloy is an important aspect in the research of Ge Sn material.This paper studies light-emitting diode, one special devices in optoelectronic devices, combined with Ge Sn alloy material research, to design a new type of Ge Sn light-emitting diodes, the Ge Sn light-emitting diodes uses pin structure, the p-doped layers and the n-doped layers use heavy doping of Si and the intrinsic i-layer in the device uses Ge Sn material and it has a thickness of 300 nm,in which the Sn content is 3%,and the doping concentration of p region is 19101? n region is 101?18, small intrinsic Ge layer is used between the the p layer and i layer, the n layer and i layer to reduce the lattice mismatch, then use software to emulate the designed device.The simulation results show that, this new type of Ge Sn light-emitting having a spectral range of 800nm-2000 nm, and has the highest luminous power around 1550 nm, and it has a high effect in the infrared communication, while, I-V characteristic simulation have been greatly improved to the traditional light-emitting diodes. After that, design numbers of Ge Sn light emitting diode devices, in which the Sn content, the intrinsic i-layer thickness, and pn doping concentration were changed, then simulate its effect on the individual characteristics of these devices. The simulation results show, Sn content of about 5% or more, the optical and electrical characteristics of the device has a relatively large increase, the intrinsic i-layer thickness of from 100nm-300 nm significantly enhance the electrical and optical characteristics of the device, and p doping concentration which is 20101? n doping concentration which is 19101? improves the photoelectric characteristics of the device most.Thus, according to these studies, select reasonable parameters to design the device with excellent spectral response and electrical characteristics, the Ge Sn light-emitting diode will play an important role in monolithic photoelectric integration and its scope of application will become more widespread.