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Theoretical Reaserch on the Application of DBRs in UV-LED

Author: LiFengJun
Tutor: WangTao
School: Tianjin University
Course: Physical Electronics
Keywords: Distributed Bragg reflector UV light - emitting diodes Al-doped concentration Refractive index
CLC: TN312.8
Type: Master's thesis
Year: 2007
Downloads: 158
Quote: 1
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Abstract


Today, the wavelength range of increasingly wide range of applications in the 350-280nm UV light emitting diode, in particular 350nm UV light emitting diodes have been used in many fields, such as environmental protection, medical device, etc. in various fields. However, due to the quantum efficiency is very low, and InGaN-based near-ultraviolet or blue light-emitting diode, 350nm UV light-emitting diode light-emitting efficiency is very low. Therefore, how to effectively improve the luminous efficiency of ultraviolet light-emitting diode has important applications. In this paper, the analysis of the ultraviolet light-emitting diode light-emitting mechanism, compared with other semiconductor light-emitting diodes and ultraviolet light-emitting diode, the Blu-ray wavelength is much larger than 362nm (GaN Bandgap), the Blu-ray diode does not exist internal absorption. This indicates that the internal absorption greatly affect the luminescence properties of the ultraviolet light-emitting diode, which is UV light-emitting diode performance is significantly lower than the near-ultraviolet and blue light-emitting diode reasons. Related studies show that, if it is placed in the distributed Bragg reflector can be a greater extent, to improve its light extraction efficiency and emission luminance. Therefore, the main contents of this paper are as follows: (1) Fully understand the overview of the Bragg reflector in the light-emitting diode, and analyzed theoretically distributed Bragg reflector used in ultraviolet light-emitting diodes can effectively suppress internal absorption , thereby obtaining a larger output energy methods and principles. (2) exploring the relationship between the concentration and the wavelength of the refraction coefficient of the DBR layer and the Al-doped obtained in the Al x Ga 1-x N in Al The higher the content of (x is larger), the larger the wavelength, the smaller the index of refraction (n) of the film conclusions. (3) Quantitative analysis of the relationship between the the DBR decision system performance in several factors, namely: the relationship between the molar concentration of Al A. layer bandgap Eg and film material B. To a solution of refraction coefficient the refractive index of AlxGa1-XN relationship between C. layer bandgap Eg between temperature and molar concentration of Al D. refraction relationship between the coefficient and the temperature (4) verify that the room temperature (T = 300K) the reliability and usefulness of the same molar concentration of Al (x) (n) the relationship of the formula (B), illustrates this relationship can be used under normal temperature the Ga if the known Al x the molar concentration of Al-x N, can be obtained the Al x the the Ga 1-x N, the refractive index of the calculation.

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CLC: > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > Semiconductor diode > Diodes: structure and performance > Light-emitting diodes
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