Zinc-blende and wurtzite GaAs quantum dots in nanowires studied using hydrostatic pressure
Zinc-blende and wurtzite GaAs quantum dots in nanowires studied using hydrostatic pressure
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使用静水压力研究纳米线中的闪锌矿和纤锌矿 GaAs 量子点
DOI：
10.1103/physrevb.92.165315
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发表时间：
2015-10-28
影响因子：
3.7
通讯作者：
Sun, Baoquan
中科院分区：
文献类型：
--
作者：
Yang, Shuang;Ding, Kun;Sun, Baoquan
我们报道了闪锌矿(ZB)和纤锌矿(WZ)两种晶体相自组装的GaAs量子点(QD)嵌入到单个的GaAs/AlGaAs核壳纳米线(NW)中。通过测量静压下的光致发光和时间分辨光致发光光谱，研究了这两种量子点的光学跃迁和单光子特性。我们发现ZB量子点是直接带隙跃迁，复合寿命短(~1 ns)，压力系数高(75-100 meV/Gpa)。相反，由于量子限制效应，WZ量子点经历了从直接带隙到伪直接带隙的转变，激子寿命显著延长(4.5-74.5 ns)，压力系数显著减小(28-53 meV/Gpa)。通过执行最先进的原子赝势计算，进一步检验了这些基本的物理性质。
We report both zinc-blende (ZB) and wurtzite (WZ) crystal phase self-assembled GaAs quantum dots (QDs) embedding in a single GaAs/AlGaAs core-shell nanowires (NWs). Optical transitions and single-photon characteristics of both kinds of QDs have been investigated by measuring photoluminescence (PL) and time-resolved PL spectra upon application of hydrostatic pressure. We find that the ZB QDs are of direct band gap transition with short recombination lifetime (~1 ns) and higher pressure coefficient (75-100 meV/GPa). On the contrary, the WZ QDs undergo a direct-to-pseudodirect bandgap transition as a result of quantum confinement effect, with remarkably longer exciton lifetime (4.5-74.5 ns) and smaller pressure coefficient (28-53 meV/GPa). These fundamentally physical properties are further examined by performing state-of-the-art atomistic pseudopotential calculations.