Effect of overgrowth temperature on the photoluminescence of Ge/Si islands
Effect of overgrowth temperature on the photoluminescence of Ge/Si islands
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DOI：
10.1063/1.1318729
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发表时间：
2000-10
影响因子：
4
通讯作者：
O. Schmidt;U. Denker;K. Eberl;O. Kienzle;F. Ernst
中科院分区：
文献类型：
--
作者：
O. Schmidt;U. Denker;K. Eberl;O. Kienzle;F. Ernst
在 630 °C 下通过分子束外延生长的 Ge/Si 岛在不同温度 Tcap 下生长有 Si，并记录了它们的光致发光光谱。与岛相关和与润湿层相关的能量跃迁均随 Tcap 降低而红移，这是通过材料混合减少来解释的。在温度下降期间引入的强制生长中断会导致岛成熟并将岛（润湿层）光致发光峰值稍微移动到较低（较高）能量。生长中断使润湿层的量子效率淬灭了一个数量级以上，而与岛相关的光致发光强度甚至略有增加。该岛对生长中断和界面污染具有卓越的抵抗力，这可以通过Ge纳米结构中的有效载流子定位来解释。据报道，在 460 °C 下生长过度的 Ge 岛会产生室温光致发光。
Ge/Si islands grown with molecular-beam epitaxy at 630 °C are overgrown with Si at different temperatures Tcap, and their photoluminescene spectra are recorded. Both the island-related and wetting-layer-related energy transitions redshift with lowered Tcap, which is explained by reduced material intermixing. The mandatory growth interruption, which is introduced during the temperature drop, causes island ripening and shifts the island (wetting layer) photoluminescence peaks slightly to lower (higher) energies. The growth interruption quenches the quantum efficiency of the wetting layer by more than an order of magnitude, whereas the island-related photoluminescence intensity even slightly increases. The island’s superior resistance against growth interruptions, and hence interface contamination, is explained by effective carrier localization in the Ge nanostructures. Room-temperature photoluminescence is reported for Ge islands overgrown at 460 °C.