Effect of interfacial states on the binding energies of electrons and holes in InAs/GaAs quantum dots
Effect of interfacial states on the binding energies of electrons and holes in InAs/GaAs quantum dots
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DOI：
10.1103/physrevb.58.6724
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发表时间：
1998-09
影响因子：
3.7
通讯作者：
A. Williamson;A. Zunger
中科院分区：
文献类型：
--
作者：
A. Williamson;A. Zunger
在{OPEN_QUOTES}自组装的{CLOSE_QUOTES}纳米结构中，InAs量子点与其GaAs帽之间的界面为非均匀应变。我们发现，这种应变可以导致由GaAs衍生的X{sub1c}型界面电子态的局域化。当施加静水压力时，这种势垒状态变为InAs/GaAs点系统的导带极小值。应变分裂了这种X{sub1c}态的简并，并预测将导致电子局域化在金字塔尖端上方的GaAs势垒中。从这种状态到空穴状态的发射能量的计算(本工作)或测量(Itskevich{ital等人)可以提供空穴结合能，{Delta}{子点}{sup(H)}。与零压电子-空穴复合能相结合，得到电子结合能{Delta}{子点}{sup(E)}。我们的计算结果表明，在P=0时，{Delta}{subDot}{sup(H)}{约}270ThinspmeV(弱压力相关)和{Delta}{sub点}{sup(E)}{约}100ThinspmeV。在P=0时，测定值分别为：{Delta}{子点}{sup(H)}{约}235thinspmeV(弱压力依赖)和{Delta}{子点}{sup(E)}{约}50ThinspmeV。我们从波函数局域化和空穴结合能与压力的依赖关系的角度考察了这些值之间的差异。{版权所有}{ital1998}{italthe American Physitive Society}
The interface between an InAs quantum dot and its GaAs cap in {open_quotes}self-assembled{close_quotes} nanostructures is nonhomogeneously strained. We show that this strain can lead to localization of a GaAs-derived X{sub 1c}-type interfacial electron state. As hydrostatic pressure is applied, this state in the GaAs barrier turns into the conduction-band minimum of the InAs/GaAs dot system. Strain splits the degeneracy of this X{sub 1c} state and is predicted to cause electrons to localize in the GaAs barrier above the pyramidal tip. Calculation (present work) or measurement (Itskevich {ital et al.}) of the emission energy from this state to the hole state can provide the hole binding energy, {Delta}{sub dot}{sup (h)}. Combining this with the zero-pressure electron-hole recombination energy gives the electron binding energy, {Delta}{sub dot}{sup (e)}. Our calculations show {Delta}{sub dot}{sup (h)}{approximately}270thinspmeV (weakly pressure dependent) and {Delta}{sub dot}{sup (e)}{approximately}100thinspmeV at P=0. The measured values are {Delta}{sub dot}{sup (h)}{approximately}235thinspmeV (weakly pressure dependent) and {Delta}{sub dot}{sup (e)}{approximately}50thinspmeV at P=0. We examine the discrepancy between these values in the light of wave-function localization and the pressure dependence of the hole binding energy. {copyright} {ital 1998} {ital The American Physical Society}