THEORY OF THE STRUCTURE AND DYNAMICS OF THE C IMPURITY AND C-H COMPLEX IN GAAS

被引:54
作者
JONES, R [1 ]
OBERG, S [1 ]
机构
[1] UNIV LULEA,DEPT MATH,S-95187 LULEA,SWEDEN
来源
PHYSICAL REVIEW B | 1991年 / 44卷 / 08期
关键词
D O I
10.1103/PhysRevB.44.3673
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Carbon is an important impurity in metalorganic molecular-beam-epitaxy-grown GaAs. C(As) is a single acceptor that can be passivated by H. We describe local-density-functional cluster calculations on the structure and dynamics of the impurities and passivated complexes. The lowest-energy structure of the passivated acceptor is a H atom located 1.1 angstrom from C in a bond-centered orientation. The H-Ga distance is 2.1 angstrom. The other three C-Ga lengths are 2.18 angstrom. The H stretch frequency is found to be 2605 cm-1 and is observed at 2635 cm-1. We have also calculated C-H bend modes that should be visible in Raman but not in infrared experiments. The activation energy for the reorientation of the complex is 0.67 eV. Also described are the local modes of the two substitutional C defects in addition to a C-C pair. Modes of the latter are found around 553 and 425 cm-1, respectively, and have effective charges of about 0.5.
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页码:3673 / 3677
页数:5
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