Study on Threshold Current Density of Semiconductor Quantum Dot Laser

• Main Authors: I-Tso Lin, 林奕佐
• Other Authors: Tei-Chen Chen
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/77073040459405139120

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 92 === 　　The technology of quantum dot laser has attracted great attention recently due to its excellent properties of high temperature and the low threshold current density. Its applications include the header of read-write of the CD-ROM drive, infrared remote sensing the optical fiber and communication and so on. Due to significant progress in manufacturing technology of quantum dot layer structure, the size and uniformity of quantum dots have achieved great improvement. Consequently, development of high performance quantum-dot laser becomes possible. 　　Recently, the techniques of quantum-well laser with two-dimensional confinement have already well developed. In the near future, the quantum-dot laser with three-dimensional confinement certainly becomes the next focus of high technology in many countries. Theoretically, the effect of the temperature and characteristic temperature on the threshold current density of quantum-dot laser is very small. However, at higher temperature, the carriers will easily by thermally exciting to the narrow region of optical confinement layer (OCL). In other words, it becomes more difficult to catch the carriers by the quantum dots. Consequently, the threshold current density of quantum dot will rise substantially. In this thesis,GaInAs and GaInAsP are selected as material of quantum dot and optical confinement layers, respectively. We focus on the state of equilibrium, non-equilibrium injections. The effects of the probability of electron and hole, the minimum of surface density, and the derivation in size and uniformity of quantum dot on the threshold current density are evaluated and discussed. The result show that on the state of non-equilibrium injections, we get 4~5 A/cm2 of threshold current density at 80K, and the relationship compare with the quantum dot laser of experiment.