Theoretical Calculations And Experimental Study On Boron-Incorporated Photoelectronic Materials

The research work of this thesis was mainly supported by the subproject "Theory on Heterogeneous Materials Compatibility and Key Structure&Technology Innovations for Monolithic Integrated Optoelectronic Devices"(No.2003CB314901).This subproject belongs to National Basic Research Program of China(also called 973 Program),named "Basic Research on Integrated Optoelectronic Devices and Microstructure Optical Fibers with Structure and Technology Innovations for Future Advanced Optical Communications"(No.2003CB314900).Professor Xiaomin Ren is the chief scientist of this 973 Program.Novel integrated optoelectronic devices are prerequisite to the evolution of the optical communications systems.And the major outstanding issues, which have been encountered with during the investigation of integrated optoelectronic devices,are the compatibilities between different materials, different structures and different processes.How to realize the integration of the heterogeneous semiconductors becomes the most critical.Besides the further optimization of heteroepitaxy technologies,the exploration of new photoelectronic materials whose lattice constant matched to GaAs or Si,and bandgap matched to the 1.3-1.55μm wavelength range of optical communications,may be the perfect resort.Theoretical and experimental research on boron- incorporated photoelectronic materials has been done in this thesis.Research results,as listed below,have been achieved.1.By the CASTEP software based on density-functional theory (DFT),the primitive-cell method and the lowest energy principle,the lattice constant and energy bandgap structure of BAs,BSb and BP under their own stable states were calculated. 2.By 32-atom super-cell model,the energy bandgap structures of B_xIn_1-xAs with different boron composition were calculated. Simulated results show that bandgap of B_xIn_1-xAs will increase with the increment of boron content.Subsequently,the bandgap bowing parameter of about 2.6eV was obtained by Vegard's law.3.The enthalpy of B_xGa_1-xAs and B_xIn_1-xAs was also calculated. Along with the increasing of boron composition,the enthalpy will increase rapidly.Thus,it can be concluded that boron can not be highly incorporated into B_xGa_1-xAs and B_xIn_1-xAs.4.B_xGa_1-xAs epilayers have been grown on the(001)GaAs substrate by LP-MOCVD using TEB,TMGa and AsH₃ sources. The boron incorporation behaviors have been studied as a function of growth temperature(T_g,)and gas phase TEB mole fraction(X_v).The experimental results show that 580℃should be the optimum growth temperature for BGaAs deposition, under which the maximum boron composition up to 5.8%was obtained.It has also been found that the boron incorporation will be enhanced with the increase of X_v value.However,there existed the critical value for X_v.5.Lattice-matched BInGaAs epilayers have also been grown on the(001)GaAs substrates at 580℃.DCXRD measurements show that the crystaUinities of the grown epilayers of BInGaAs were really good.