Growth and Critical Layer Thickness Determination of Indium Gallium Nitride Films Grown on Gallium Nitride

netal organic chemical vapor deposition;gallium phosphide;photodetectors;bowing parameter;band gap dependence on composition;indium gallium nitride;critical layer thickness

Parker, Christopher Arlen ; Dr. Kwiok Kim, Committee Member,Dr. Salah M. Bedair, Committee Chair,Dr. James F. Kauffman, Committee Member,Dr. Robert J. Nemanich, Committee Member,Parker, Christopher Arlen ; Dr. Kwiok Kim ; Committee Member ; Dr. Salah M. Bedair ; Committee Chair ; Dr. James F. Kauffman ; Committee Member ; Dr. Robert J. Nemanich ; Committee Member

University:North Carolina State University

关键词: netal organic chemical vapor deposition;    gallium phosphide;    photodetectors;    bowing parameter;    band gap dependence on composition;    indium gallium nitride;    critical layer thickness;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/4426/etd.pdf?sequence=1&isAllowed=y

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【 摘 要 】

Many of the physical properties between strained epilayers and relaxed epilayers can be different. A critical layer thickness (CLT) can be determined by measuring these properties and observing the transition point at which they change. The main purpose of this dissertation is to determine the CLT of In[subscript x]Ga[subscript 1-x]N /GaN material system primarily by determining the onset of photoluminescent band-edge emission red-shift as a function of InxGa1-xN thickness between strained and relaxed InxGa1-xN films. The CLT determination by this method for both In[subscript x]Ga[subscript 1-x]N/GaN single heterostructures and In[subscript x]Ga[subscript 1-x]N/GaN double heterostructures were in good agreement and the CLT for InGaN layers where approximately 25 nm, 40 nm, and 80 nm for InN compositions of 16%, 10%, and 5%, respectively.In addition, the optical band gaps as a function of In[subscript x]Ga[subscript 1-x]N over 0≤x≤0.25 for strained and relaxed films were determined. Band-gaps deduced from optical transmission measurement techniques were in good agreement with the optical band-gaps determined by PL emission measurements for very thick relaxed In_xGa_1-xN films. The composition for very thin strained In[subscript x]Ga[subscript 1-x]N was assumed to be the same as the composition for the relaxed In[subscript x]Ga[subscript 1-x]N. The band-gap's dependence on InN mole fraction, x, for strained and relaxed In[subscript x]Ga[subscript 1-x]N films was fit to a parabolic function with strained and relaxed film bowing parameters of 2.1259 eV and 2.7503 eV, respectively, using a relaxed InN band-gap endpoint of 0.77 eV (3.4159 eV and 4.112 eV, respectively, using a relaxed InN band-gap endpoint of 1.89 eV). The bowing parameter, especially, the bowing parameter for the relaxed In[subscript x]Ga[subscript 1-x]N film was compositionally dependent (b=f(x)) with a bowing parameter of 3.76 eV and 2.58 eV (using a relaxed InN band-gap endpoint of 0.77 eV) or 5.02 eV and 3.97 eV (using a relaxed InN band-gap endpoint of 1.89 eV) for composition regions 0.05