Ge hut cluster luminescence below bulk Ge band gap
Ge hut cluster luminescence below bulk Ge band gap
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DOI：
10.1063/1.1537437
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发表时间：
2003-01-20
影响因子：
4
通讯作者：
Sigg, H
中科院分区：
文献类型：
--
作者：
Denker, U;Stoffel, M;Sigg, H
我们报告了 Si(001) 上 Ge 簇团岛的光致发光 (PL) 特性，这些岛团在低至 250 摄氏度的温度下过度生长。我们发现，随着过度生长温度从 500 摄氏度降低到 360 摄氏度，与岛相关的光致发光系统地红移，这归因于 Ge 偏析的减少。对于更低的过度生长温度，发射能量饱和在 0.63 eV 或 1.96 mum，比无应变块体 Ge 的带隙小 110 meV 以上。我们报告了在低激发功率下以 2.01 μm 为中心的 PL 峰，与限制在应变 Ge 岛中的空穴与限制在周围 Si 基体中的电子之间的空间间接跃迁的估计跃迁能量非常一致。在高达 185 K 的温度下观察到 PL，并通过拟合与温度相关的峰强度推导出 40 meV 的活化能。退火实验揭示了与小屋簇相关的 PL 的系统蓝移，从而明确验证了 PL 信号源自小屋簇而不是缺陷。 (C) 2003 年美国物理研究所。
We report on the photoluminescence (PL) properties of Ge hut cluster islands on Si(001) that were overgrown at temperatures as low as 250 degreesC. We find that the island-related photoluminescence systematically redshifts as the overgrowth temperature is reduced from 500 to 360 degreesC, which is attributed to a reduced Ge segregation. For even lower overgrowth temperatures, the emission energy saturates at 0.63 eV or 1.96 mum, more than 110 meV smaller than the band gap of unstrained bulk Ge. We report a PL peak centered at 2.01 mum at low excitation power, in good agreement with the estimated transition energy for a spatially indirect transition between holes confined in the strained Ge island and electrons confined in the surrounding Si matrix. PL is observed up to a temperature of 185 K and an activation energy of 40 meV is deduced from fitting the temperature-dependent peak intensity. Annealing experiments reveal a systematic blueshift of the hut cluster-related PL, thus verifying unambiguously, that the PL signal originates from the hut clusters and not from defects. (C) 2003 American Institute of Physics.