Development of device structures with simultaneous optical and electronic confinement and microscopic transmission measurements on their lasing, absorption, and gain characteristics

我们开发了量子线激光器等同时具有光和电子限制的新型器件结构，并基于我们的微观光传输测量系统研究了它们的激射、吸收和增益特性。我们首次开发了用于电子和光子量子限制结构设计和优化的有限元计算代码。我们还开发了不同温度下的光泵浦激光、顶视光致发光光谱和图像以及波导传输光的测量系统。对于劈边过生长T形量子线激光器结构，我们研究了（110）过生长表面的界面粗糙度问题，它限制了结构的最终质量，并通过引入一种新的生长中断退火方法解决了这一问题。最终实现了横向延伸数十微米的无台阶原子级平坦界面，并将单模一维量子线与单模一维光波导相结合，制成了单量子线激光器。我们在2001年8月首次观测到它的激光发射。该激光器结构包括在一维光波导中的二维量子威尔斯阱和三维双异质结构以及在二维平板光波导中的二维量子阱。换句话说，它包含1D-电子-1D-光子以及2D-电子-1D-光子、3D-电子-1D-光子和2D-电子-2D-光子的结构。此外，这些结构都产生激光，因此我们可以同时比较所有结构的激光特性。此外，我们还分辨了一维激子和一维连续态的吸收光谱，并首次观察到一维系统固有的索末菲因子。

We develop novel device structures with simultaneous optical and electronic confinement such as quantum wire lasers, and study their lasing, absorption, and gain characteristics on the basis of our microscopic optical transmission measurement systems.We first developed computation codes with the finite element methods for design and optimization of quantum-confined structures for electrons and photons. We also developed measurement systems for optically pumped lasing at various temperatures, top-view photoluminescence spectra and images, and transmission light from waveguides.As for the cleaved-edge overgrown T-shaped quantum wire laser structures, we investigated the problem of interface roughness on (110) overgrowth surfaces, which limit the final quality of the structures, and resolved the problem by introducing a new growth interruption annealing method. We finally realized atomically flat interface without monolayer steps over several tens of micro-meters in lateral extent.A single quantum wire laser, which is a combination of a single-mode 1-D quantum wire and a single-mode 1-D optical waveguide was fabricated. We observed its lasing for the first time in August 2001. The laser structure includes 2-D quantum wells and 3-D double-hetero-structures in the 1-D optical waveguide and a 2-D quantum well in a 2-D slab optical waveguide. In other words, it contains structures of 1D-electron-1D-photon together with 2D-electron- 1D-photon, 3D-electron-1D-photon, and 2D-electron- 2D-phbton. Furthermore, these structures all make lasing, so that we can compare lasing characteristics of all the structure simultaneously. In addition, we resolved absorption spectra of 1-D excitons and 1-D continuum states, and observed the Sommerfeld factor inherent to 1-D systems for the first time.