Theoretical And Experimental Investigations On Boron Incorporated Ⅲ-Ⅴ Quaternary Optoelectronic Materials

With the development of optical communications system, increasing demand for the functionality and stability of optoelectronic devices is needed, which leads to the research on optoelectronic devices shift from the discrete to integrated one. In order to solve the problem of the compatibilities between different materials encountered during monolithic integration, the exploration of new optoelectronic materials whose lattice constant matches are matched to GaAs or Si, may be the perfect resort.The thesis is mainly focused on the theoretical calculations of band-gap properties of quaternary BxGa1-xNyAs1-y lattice-matched to Si, and experimental research on highly-strained B-incorporated InGaAs/ GaAs QWs. Research results, as listed below have been achieved.(1) By SQS-8 supercells, we calculated the band-gap energy and bowing parameter of BxGa1-xN、BNxAs1-x、BxGa1-xAs and GaAsxN1-x, respectively. The calculation results show that B incorporation into GaAs or GaN leads to small band-gap bowing parameter, the threotical direct band-gap bowing parameter are 5.36eV and 2.6eV for BxGa1-xN and BxGa1-xAs. While N incorporation into GaAs or BAs leads to strong band-gap bowing, the direct band-gap bowing parameters are 10.07eV for BNxAs1-x and 8.3eV for GaAsxN1-x.(2) We calculated the band-gap properties of BxGa1-xNyAs1-y alloy with different boron (B) composition. The theoretical result shows that direct band-gap energy of 0.8eV can be obtained for BxGa1-xNyAs1-y alloy lattice-matched to Si when boron (B) composition is 6% and nitrogen (N) content is 15%. (3) Five-period highly-strained InGaAs/GaAs MQWs are successfully grown on GaAs (100) substrates by LP-MOCVD. The DCXRDω-2θscan and room temperature PL measurements show Ino.4Gao.6As/GaAs MQW structures without relaxation have been grown at 480℃,and the room temperature PL peak wavelength MQWs reached 1191nm.(4) Optical properties and crystal quality of boron (B) incorporated InGaAs/GaAs MQWs grown by LP-MOCVD are studied. The results show that boron (B) incorporation into InGaAs leads to the decrease of the lattice constant and indium (In) composition of InGaAs, and also lead to the decrease of peak splitting of XRD patterns and the blue-shift of RT-PL peak wavelength. When the flow rate of TMGa and TEB are fixed during the growth, it has been found that if we further increase the TMIn flow rate, the RT-PL peak wavelength will be red-shifted definitely and no relaxation will occur.