Investigation of GaN/AlGaN Multiple Quantum Disks

• Main Authors: Tung-Wei Chi, 紀東煒
• Other Authors: Li-Wei Tu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/92639184970813806349

碩士 === 國立中山大學 === 物理學系研究所 === 92 === In this thesis, two series of self-assembled GaN and AlxGa1-xN nanorods are grown by plasma-assisted molecular beam epitaxy (PAMBE) on Si(111) wafer. The Al contents in AlxGa1-xN nanorods is varied from 6% to 75% by changing the Al cell beam flux (BFM). Second, the GaN/AlGaN multiple quantum wells (MQWs) with variation thickness are grown on the GaN nanorods with a p-GaN layer on the top. Al concentration is determined by electron probe x-ray micro-analysis (EPMA) and x-ray diffraction (XRD). The reflection high-energy electron diffraction (RHEED) and scanning electron microscopy (SEM) images show that the height, density and morphology of nanorods depend on the Al content. The (micro-)PL, CL and Raman spectra also show the variation of the characterization from those of GaN to AlN. The transmission electron microscopy (TEM) images show that the GaN/AlGaN MQWs structures with well widths of 1, 2, 3, 4, 6, 8 and 16 c-LC (Lattice constant on c-direction) were successful grown on the nanorods. The (micro-)PL and CL spectra show red-shift of the peak position with the decrease of Mg-doped concentration. When the well thickness is less then 4 c-LC, the CL spectra show blue-shift of the peak position with the decrease of the well thickness due to the Quantum-confined effect and the polarization effect in MQWS.