Study On The Growth Evolution Mechanism And Optical Properties Of InGaN Epitaxial Materials With Modifiable Wavelength

With the increasing demand for higher luminous efficiency and full-spectrum luminescence,the performance requirements of semiconductor devices are becoming higher and higher,and new device structures are constantly emerging.As the core functional layer of Ga N-based devices,InGaN epitaxial materials play an important role in improving the photoelectric performance of devices.However,due to the low miscibility of In N and Ga N,high dislocation density and uneven distribution of indium(In)components in high-component long-wavelength InGaN epitaxial materials have seriously affected their luminescence characteristics.The past two-dimensional quantum wells The structure has been difficult to obtain high-quality green and red epitaxial structures.Therefore,exploring and growing new InGaN epitaxial structures is very important to solve the above problems.InGaN quantum dots and InGaN micrometer materials have a special quantum size effect,which can well improve the problem of uneven distribution of In components and difficult to incorporate,and obtain long-wavelength green and red light.At the same time,it has a strong limiting effect on the carriers in the active area,preventing the transfer of carriers to the non-radiative recombination center in the material,and effectively improving the internal quantum efficiency.Therefore,this paper studies the growth evolution mechanism and optical properties of these two tunable wavelength InGaN epitaxial materials.The specific research contents and results are as follows:(1)In order to explore the influence of the well / barrier interface changes on the structure of the active region,high-quality green-light InGaN quantum dot epitaxial materials were prepared.The influence of the growth rate of the cap layer(Cap)on the morphology and In composition of the InGaN epitaxial material was studied.The flow rates of the cap layer of 20 sccm,40 sccm and 60 sccm were designed.When the flow rate of the Cap layer is 40 sccm,In atoms and Ga atoms migrate to a stable state on the surface of the three-dimensional structure,resulting in uniform and dense quantum dots with an average diameter of 172 nm.Raman spectroscopy shows that InGaN quantum dots with a growth rate of Cap layer of 40 sccm have higher quality crystallization performance,and the In composition of the active region increases.In order to further clarifythe growth evolution mechanism and luminescence optical properties of the active region of InGaN epitaxial materials,the effect of InGaN / Ga N cycle number on epitaxial quantum dots was continued to be studied.When the number of growth cycles increases from 1 to 5,the average diameter of InGaN QD becomes 122.70 nm;the emission wavelength reaches 545 nm;its internal quantum efficiency increases from 8.22% to 8.74%.In addition,the growth-explaining mechanism of InGaN's analytical-migration-adsorption growth process was explained through the growth evolution mechanism,which provided experimental data support for improving the crystal quality and luminescence performance of InGaN quantum dots.(2)In order to obtain full-spectrum luminescence with different In composition distributions,the study of InGaN microepitaxial materials with adjustable wavelength was continued.The influence of the number of InGaN /Ga N cycles on the growth mechanism and optical properties of the active region of the micrometer mesa material was explored.When the number of InGaN /Ga N cycles increases from 1 to 5,the polarization intensity decreases and the distribution of In atoms on the semipolar plane is different,which is the ideal state for obtaining white light InGaN multiple quantum wells.The luminescence peaks of InGaN microstages with different cycle periods were analyzed by micro-area photoluminescence spectroscopy,and three peaks at 447 nm,525 nm and 618 nm were obtained.As the growth period increases from 1 to 5,the luminescence of the hexagonal micrometer stage gradually becomes uniform,and the luminescence performance is greatly improved.The high crystalline orientation of the InGaN micrometer table is divided by electron backscattering and Raman spectroscopy.When the InGaN micrometer table is cycled for 5cycles,its growth direction tends to be unified,which provides a good application for the InGaN epitaxial material applied to micrometer LED Experimental basis and theoretical basis.