Piezospectroscopy and ab-initio calculations of carbon-oxygen complexes in gallium arsenide

用低温傅里叶光谱研究了砷化镓(GaAs)中的碳氧络合物(C，O)的中红外光谱。背景是提拉法(LEC)和布里奇曼法(VGF)生长的砷化镓单晶中轻元素相互作用的研究。无意间或故意引入碳和氧，以调整其电学性质。其目的是阐明(C，O)中心的微观缺陷结构。在先前的项目中，已经成功地在[100]、[110]和[111]晶体方向上成功地进行了高达0.2 Gpa的单轴压力的压电谱测量。(C，O)中心具有四角点对称性。同位素位移(18O，12C)吸收带的强度与18O同位素的自然丰度不相对应。在目前的继续项目中，建议将16O/18O和12C/13C注入到纯的GaAs衬底中，并通过快速热退火来有意地产生不同的同位素移位(C，O)吸收带。澄清络合物中涉及的氧原子数量是工作的重点。同时计划进行从头算计算，以测试满足所需对称性的(C，O)中心的稳定性和振动性质。

A carbon-oxygen complex (C, O) in gallium arsenide (GaAs) will be investigated by Fourier spectroscopy at low temperatures in the mid infrared. Background is the interest in light-element interactions in GaAs single crystals grown by Czochralski (LEC) or Bridgman (VGF) methods. Carbon and oxygen are introduced either inadvertently or deliberately to adjust to electrical properties. It is the aim to clarify the microscopic defect structure of the (C, O) center. During the previous project piezospectroscopic measurements have been performed successfully up to uniaxial pressure of 0.2 GPa in the [100], [110], and [111] crystallographic directions . The (C,O) center has tetragonal point symmetry. The intensity of the isotope shifted (18O, 12C) absorption band does not correspond to the natural abundance of the 18O isotope. In the present continuation of the project it is suggested to implant the isotopes 16O/18O as well as 12C/13C into pure GaAs substrates and to anneal the samples by rapid thermal annealing to generate the different isotope shift (C, O) absorption bands deliberately. The clarification of the number of oxygen atom involved in the complex is in the focus of the work. Ab-initio calculations are planned in parallel to test the stability and vibrational property of (C, O) centers fulfilling the required symmetry.