Quantum Dots Laser of Coupled microdisk-ring structure

• Main Authors: Sung-Yin Tsai, 蔡松穎
• Other Authors: Tsong-Sheng Lay
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/77061785529475446234

碩士 === 國立中山大學 === 光電工程學系研究所 === 99 === In this thesis, we used the E-Beam lithography to fabricate a device of coupled microdisk-ring laser on the sample which was grown by molecular beam epitaxy (MBE), and analyzed the coupled effect of the device. The active layer was composed of six compressively strained InGaAs quantum dots (QDs) that were designed to support gain at 1200nm. Under the active layer, we replaced sacrificial layer by distributed bragg reflector (DBR). The purpose of the DBR was used like a mirror to reflect the particular wavelength which located at DBR’s stop band, so the energy would be confined in the active layer. The device was composed of a microdisk and a ring. The diameter of the microdisk was 3μm, and the width of the ring is 250nm. The microdisk was placed in the ring, and the gap of both was 100nm. After design, we simulated whether the device could generate coupled modes by Finite-Difference Time-Domain (FDTD). In experiment, we used the E-Beam lithography to define negative pattern on the sample which is spread with the PMMA. We also used the thermal evaporation to evaporate the metal, and lift the metal to form our pattern. Finally, we used the dry etching to transform the pattern to the epitaxial layer, and then the device was completed. In measurement, we used the micro-PL to measure our device, and got a successful result. The result showed our device generated eight resonant modes. The measured result matched the simulation result. Through simulation, the device generated three coupled modes, 1173.8nm, 1206nm, and 1214nm. We expect that the device will be used to generate terahertz source in the future.