Optical properties of a silver-related defect in silicon
Optical properties of a silver-related defect in silicon
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硅中与银相关的缺陷的光学特性
DOI：
10.1103/physrevb.67.235111
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发表时间：
2003
影响因子：
3.7
通讯作者：
Meng
中科院分区：
文献类型：
--
作者：
G. Davies;T. Gregorkiewicz;M. Z. Iqbal;M. Kleverman;E. C. Lightowlers;N. Vinh;Meng
用银掺杂晶体硅会产生接近 778.9 meV 的多重零声子结构的光致发光中心。我们表明，已发表的电子振动边带的分配是错误的，这对激发态发光跃迁的相对跃迁概率具有严重影响。在低温下，大部分发光强度来自通过中心两个激发态的声子辅助耦合与禁零声子线相关的声子边带。振动的有效质量由同位素效应确定，接近于一个银原子的质量。单轴应力和磁扰动表明当前中心电子结构的分配是不正确的，并且最好通过“伪供体”模型的新变体来描述。电子在有效 Td 环境中运行，轨道三重态为其最低能态，给出 j 53/2 电子态。紧密束缚的空穴的轨道角动量被中心的 C3v 对称性淬灭，仅留下自旋角动量 (s51/2)。这些粒子耦合产生 J52,1,0 状态。使用该模型，可以理解总发光强度和测量的辐射衰减时间的温度依赖性。这些数据允许对电子从有效质量激发态到导带的热诱导跃迁速率进行估计。
Doping crystalline silicon with silver results in a photoluminescence center with multiplet zero-phonon structure near 778.9 meV. We show that the published assignments of the vibronic sidebands are wrong, with severe implications for the relative transition probabilities of the luminescence transitions from the excited states. At low temperature, most of the luminescence intensity derives from the phonon sideband associated with a forbidden zero-phonon line through the phonon-assisted coupling of two of the excited states of the center. The effective mass of the vibration is determined from isotope effects to be close to the mass of one Ag atom. Uniaxial stress and magnetic perturbations establish that the current assignment of the electronic structure of the center is incorrect and that it is best described by a new variant on the ‘‘pseudodonor’’ model. An electron orbits in an effective Td environment, with an orbital triplet as its lowest-energy state, giving a j 53/2 electron state. A tightly bound hole has its orbital angular momentum quenched by the C3v symmetry of the center, leaving only spin angular momentum (s51/2). These particles couple to give J52,1,0 states. Using this model, the temperature dependence of both the total luminescence intensity and measured radiative decay time can be understood. These data allow an estimate to be made of the thermally induced transition rate of the electron from the effective-mass excited states into the conduction band.