| The breakthrough of nano-fabrication and nano-manufacturing technologies greatly promote the development of the novel low-dimensional semiconductor materials in the microelectronics,optoelectronics and other fields.As the request of the controlled growth of low-dimensional semiconductor increases with the development of science,currently to use the nano-manufacturing to controll the growing of low-dimensional semiconductor has been a significant issue.And up to now,quantum dots and nano wires with a good order have been successfully produced on patterned substrates which are fabricated by various nano-manufacturing technologies.However,the limitations of contamination pollution,material damages,complicated process,low efficiency and high cost have still challenged it a lot.To cope with the aforementioned challenges,we creatively designed and built an integrated vacuum platform combining a four-beam interference system of UV pulsed laser with the ?-? MBE equipment.Then an explorative study of the laser in-situ modifying and patterning materials based on ?-? MBE was carried out and the main contents are described below:1.Periodic nano-structure was prepared on the arsenic capping layer by in situ irradiation of pulsed laser interference.Both of the capping temperature and deposition temperature of arsenic were first studied by BFM and RHEED.Then the arsenic-response to the in situ laser stimulation was performed at a defined temperature and various kinds of periodic arsenic nano-structures have been produced.Finally,we also give a prospect for the promising applications of such arsenic structures.2.We studied the laser control to the Ga atoms migration through the in-situ laser irradiation of Ga(In)As and GaAs materials.The main research contents include:(1)the substrate temperature plays a role during the process of laser interference making the periodic Ga(In)As surface;(2)the optical excitation effect plays a main role when the laser irradiates the Ga(In)As surface;(3)the high crystal quality of patterned substrate surface was confirmed by substrate annealing;(4)we analysed the patterned GaAs surface which had been created adopting laser irradiation using the optical thermal effect;(5)ordered Ga droplets were fabricated by laser interference with high energy density;(6)quantum rings were fabricated by crystallizing Ga droplets.3.The fifth chapter,we studied the laser control to the In atoms migration through the In situ laser irradiation on InAs/GaAs and GaAs/InGaAs/GaAs materials,including:(1)the relationship between the laser density and the nucleation of the InAs nano-structures in the InAs wetting layer during the laser irradiation;(2)the observation and the analysis of the InGaAs transfering from 2D to 3D during the laser irradiation;(3)according to the study of this chapter;(4)a model was proposed on long-range-order self-organized QDs formed by patterned strain fields by in-situ laser interefernce patterning.In summary,we use UV pulsed laser irradiation on the surface of ?-? materials to in situ regulate surface atomic motion,resulting in a variety of periodic structures. |
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