Fabrication and Characterization of Atomic Layr Controlled Quantum Nano-structures

基于原子层外延(ALE)择优生长，发展了具有原子级精度的低维量子结构(尺寸、形状、成分、排列和掺杂控制)的先进控制技术，为未来的量子器件提供了新的选择。(1)局域AlE在纳米空间的生长机理和逐层生长模式切换技术研究发现，AlE的选择性生长使半导体结构的控制成为可能，甚至在纳米尺度范围内(局域AlE)，这是由于自限制效应。利用对生长顺序的控制，发展了在各向异性和各向同性ALE生长之间的逐层生长模式切换技术。(2)利用ALE生长模式切换技术发展了低维量子结构的制备工艺De…成功地实现了更发达、更矩形的量子线结构。本研究利用先进的ALE技术制备了低维原子层状短周期超晶格，用于控制量子纳米结构中的“构型”和“排列”。(3)讨论了数字刻蚀技术的发展：利用可调谐的联合国激光控制表面反应，利用可调谐的紫外光对GaAs进行数字刻蚀。研究发现，要实现数字刻蚀过程中的自限幅效应，必须在注入夹杂剂(Cl2)和激光照射之间交替进行。(4)观察和分析低维量子结构中的量子尺寸效应。荧光发射和光致发光光谱的偏振相关性证实了一维限制效应对结构的影响。P型调制掺杂线结构的光致发光还观察到了由于能带混频效应引起的价带上的特殊电子态。还观察到了发光线的抗磁位移。较少

Advanced technologies of controlling low-dimensional quantum structures (i.e.size, shape, composition, arrangement and doping control) with atomic-level accuracy were developed, based on atomic layr epitaxy (ALE) selective gwowth, for the future quantum devuces. The results o this study are summarized as follows.(1) Growth mechanism of localized-ALE in nano-space, and layr-by-layr growth mode switching techniqueIt has been found that ALE selective growth makes the control of semiconductor structures possible even in nanometer scale area (Localized-ALE), which is due to the self-limiting effect. Also layr-by-layr growth mode switching technique between anisotropic and isotropic ALE growth, using control of the growth sequence, was developed with the concept as a "selective-control of surface-processes".(2) Development of fabrication processes of low-dimensional quantum structures using ALE growth mode switching techniqueFabrication processes of low-dimensional quantum structures were de … More veloped, and rectangular shaped quantum wire structures were successfully realized. In this study, the fabrication of low dimensional atomic layr short-period superlattice by using the advanced ALE techniques were demonstrated, for the control of "conposition" and "arrangement" in quantum nano-structures.(3)Development of Digital-etching : Control of surface reaction by tunable UN laserDigital-etching of GaAs using tunable UV laser was discussed. It was found that alternative procedures between feed the enchant (Cl_2) and laser beam irradiation with precious wavelength is necessary to realize the self-limiting effect in digital etching process.(4) Observation and analysis of quantum size effects in low-dimensional quantum structures.Photoluminescence (PL) measurements on GaAs/GaAsP rectangular shaped quantum wires have been performed. One dimensional (1D) confinement effect on the structures has been confirmed by the PL emission and the polarization dependence of the PL spectra. Also the particular electronic states on valence band in the wires, whhich is due to the band mixing effect, was observed by the PL emission from the p-type modulation doped wire structures. Diamagnetic shift of PL emission from the wires also observed. Less