生長於氧化鉺/氧化釓緩衝層(111)面矽基板上氮化鎵薄膜結構與光學特性之研究

Abstract

The structural and optical characteristics of GaN film deposited on Er2O3/Gd2O3-coated (111) Si were studied using double-crystal x-ray rocking curve (DCXRC), high resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) spectroscopy in this thesis. By comparing the DCXRC signals of (11 ‾02)GaN and (12 ‾12)GaN asymmetric planes and (0002) GaN symmetric plane, respectively, it was found that, most of the TDs in GaN of the GaN/ Er2O3/Gd2O3/(111)Si sample are type a TDs in nature. Based on the results of DCXRC studies, it is believed that the FWHM of (11 ‾02)GaN and (12 ‾12)GaN asymmetric planes are primarily due to the contributions of the 1/3 GaN components of the Burgers vectors of type a and type c+a TDs on the interplanar spacing distortions of (11 ‾02)GaN and (12 ‾12)GaN planes in GaN of the GaN/ Er2O3/Gd2O3/(111)Si sample. Using invisibility criterion g ∙ b = 0, various types of dislocations in GaN film were further identify. HRTEM observations revealed the presence of extrinsic SFs and Frankel PDs in GaN near the GaN/ Er2O3/Gd2O3 hetero-interface. Strong PL emissions indicate that high quality GaN can be achieved by employing certain optimized Er2O3/Gd2O3 buffer layer structures.