Optical and Material Studies of InGaN/GaN Multi-Quantum Wells Light Emitting Diodes and Thin Films of GaGdN and GaCrN

• Main Authors: I-Hsiang Hung, 洪奕翔
• Other Authors: Zhe-Chuan Feng
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/22972360647790172836

碩士 === 臺灣大學 === 光電工程學研究所 === 98 === This thesis mainly divides into two parts: the first part is analyzed the optical properties and material characteristics of InGaN/GaN multi-quantum wells LED structure. By the Raman scattering, X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), photoluminescence excitation (PLE), time-resolved photoluminescence (TRPL) experiments were carried out to study the optical and material structure properties; the second part is studied on the optical properties of GaGdN and GaCrN thin films. (1) InGaN/GaN MQW LEDs with different Barrier widths structures: We studied the optical and material structure properties of the blue emission MQW LED samples with different barrier widths (25 Å, 40 Å, 75 Å, 150 Å and 300 Å) near the top layer. First, from the XRD experimental results, we can determine the period thickness and indium composition of the samples. From the Photoluminescence, photoluminescence excitation and time-resolved photoluminescence experiments, we can find that the luminescence efficiency is higher and the decay time is small on the sample with thinner barrier widths. The experimental results shown here can serve as important clue for the enhancement of the luminescence efficiency in the future optoelectronic devices. (2) GaGdN and GaCrN thin films by MOCVD: Second, we discussed the metal elements (gadolinium and chromium) doped on GaN grown by metal organic chemical vapor deposition (MOCVD) with different concentration. GaGdN and GaCrN thin films are dilute magnetic semiconductors (DMS). The unique advantage of DMS is that they can exhibit ferromagnetism in materials compatible with those used for solid state electronics and optoelectronics. Here, we studied the optical characteristics on GaGdN and GaCrN thin films by Raman scattering and photoluminescence spectra.