陳永芳臺灣大學：物理研究所王甫青Wang, Fu-CingFu-CingWang2007-11-262018-06-282007-11-262018-06-282007http://ntur.lib.ntu.edu.tw//handle/246246/54566In the first part of this thesis, we report the investigation of GaN epifilm by means of the cross-sectional micro-Raman scattering and cathodoluminescence (CL) spectra. We find the direct evidence for the existence of the residual thermal compressive strain along the growth direction in GaN epifilm. This result is useful for the understanding of the depth dependence of the physical properties of GaN epifilm. In the second part, we study patterned GaN grown on sapphire using the micro-Raman scattering and micro-Photoluminescence (PL) spectra. We find the direct evidence that the stress gradually relaxes when measurements approach to the stripe edge and a larger compressive stress relaxes in the smaller patterned stripe.Contents List of Figures ………………………………………………..………………… Ⅲ 1. Introduction ................................................................................................... 1 2. Theoretical background ............................................................................. 6 2.1 Raman spectroscopy .................................................................................... 6 2.1.1 Introduction to Raman scattering ...................................................... 6 2.1.2 Stokes shift and Anti-Stokes shift ...................................................... 8 2.1.3 Application of Raman spectroscopy ................................................... 12 2.1.4 Raman spectroscopy apparatus ........................................................... 13 2.2 Luminescence spectroscopy ......................................................................... 18 2.2.1 Introduction to luminescence .............................................................. 18 2.2.2 Direct and indirect band gap ............................................................... 18 2.2.3 Recombination processes ……………………………..……………. 21 2.2.4 Photoluminescence (PL) …………………………..………..……… 24 2.2.5 Cathodoluminescence (CL) ……………………………………..…. 25 3. Residual thermal strain in thick GaN epifilms revealed by cross-sectional Raman scattering and Cathodoluminescence spectra ………………………………..………………………………………. 31 3.1 Introduction .................................................................................................. 31 3.2 Fabrication of Sample …............................................................................... 32 3.3 Experimental setup …................................................................................... 33 3.4 Results and Discussion …............................................................................. 33 3.4.1 Normal Incidence Raman Spectroscopy of GaN ………….………. 33 3.4.2 Cross-sectional Raman Spectroscopy of GaN ……………….……. 38 3.4.3 Cross-sectional CL Spectroscopy of GaN ……………………...…. 44 3.4.4 Estimate of the percentage residual thermal strain ……………..…. 46 4. Stress relaxation in patterned GaN grown on sapphire ………...... 51 4.1 Introduction .................................................................................................. 51 4.2 Fabrication of Sample ................................................................................... 52 4.3 Experimental setup ....................................................................................... 52 4.4 Results and Discussion .................................................................................... 53 4.4.1 Micro-PL Spectroscopy of Pattered GaN …………...…………….. 53 4.4.2 Micro-Raman Spectroscopy of Pattered GaN ………..….………… 57 5. Conclusion ….................................................................................................... 61en-US氮化鎵應力應變拉曼光致螢光陰極射線螢光GaNstressstrainRamanPhotoluminescenceCathodoluminescencethesis