Room-temperature device application of one- dimensional-exciton photo-emission in quantum wires

为了实现一维GaAs量子线（QWR）光电发射器件，我们从物理和材料的角度研究了从低温到室温的一维激子效应及其抑制因素。为此，我们研制了具有高分辨率和高效率的显微光致发光（PL）成像和光谱系统，并尝试在T形量子线中引入In GaAs材料来稳定ID激子。结果表明，QWR的横向限制能增加到35 meV，这是大约两倍大于相应的GaAs T-QWR的观察到的18 meV。光致发光的温度依赖性表明，激子在150 K以下是稳定的。AlAs势垒的引入将进一步稳定ID激子，使其在室温下发光。T-QWR的主要困难在于在解理的（110）晶体表面上的MBE生长。利用原子力显微镜和我们的显微光致发光成像和光谱系统研究了GaAs（110）分子束外延表面。观察到了（110）表面所固有的微米尺度的大平台结构和由此产生的调制电子态，这有助于激子在不同温度下的扩散和热激活过程，并设计、制备了具有低可控性但固有强约束的脊状QWR激光器。它们在室温下确实产生了激光，我们研究了微观起源，温度依赖性和均匀性。

We have investigated the one-dimensional (1D) exciton effect from low up to room temperature and preventing factors in the physics and material point of view in order to achieve 1D GaAs quantum wire (QWR) photo-emission devices. For this purpose, we have developed microscopic photoluminescence (PL) imaging and spectroscopy system with high resolution and efficiency which is stable against temperature variation.Introduction of In GaAs material to T-shaped quantum wires was tried to stabilize the ID excitons. It turned out that the lateral confinement energy of QWR was increased to 35meV, which is about two times larger than 18meV observed for the corresponding GaAs T-QWRs. The temperature dependence of PL have shown that excitons are stable up to 150K in the sample. Introduction of AIAs barrier will further stabilize the ID excitons to make PL at room temperature.The major difficulty of T-QWRs lies in the MBE growth on the cleaved (110) crystal surface. We have investigated (110) MBE-grown surface of GaAs of atomic force microscopy and our microscopic PL imaging and spectroscopy system. The micrometer-scale large terrace formation inherent to (110) surface and the resulted modulated electronic states were observed, which contributes to the exciton diffusion and thermal activation processes at various temperatures.Ridge QWR lasers with low controllability but with inherently strong confinement have been also designed, fabricated, and characterized. They did lase at room temperature, on which we studied microscopic origin, temperature dependence, and uniformity.