Carrier dynamics in type-II GaSb/GaAs quantum dots
Carrier dynamics in type-II GaSb/GaAs quantum dots
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DOI：
10.1103/physrevb.57.4635
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发表时间：
1998-02-15
影响因子：
3.7
通讯作者：
Alferov, ZI
中科院分区：
文献类型：
--
作者：
Hatami, F;Grundmann, M;Alferov, ZI
研究了第二类(交错能带阵列)GaSb/GaAs量子点自组织阵列中载流子的光学性质和动力学。第二类量子点的能带间吸收被证明；量子点吸收峰的能量位置与光致发光光谱中的位置一致。(Sb，As)掺杂的Sb扩散长度约为1 nm，对观察到的跃迁能有重要贡献。随着激发密度的增加，偶极层的形成和量子点态的填充有助于发光的蓝移。电子与局域空穴的复合速率在很大程度上取决于平均载流子密度。当几个载流子局域在每个点上时，观察到的衰变时间常数约为5 ns，非常类似于I型系统。单个空间间接激子的衰减具有更大的时间常数，接近1微米S。量子点发光的衰减时间与测量范围内的温度无关，T小于或等于零维激子的预期温度T。[S0163-1829(98)04907-8]。
The optical properties and dynamics of charge carriers in self-organized arrays of type-II (staggered band lineup) GaSb/GaAs quantum dots are studied. Interband absorption from type-II quantum dots is evidenced; the energetic positions of quantum dot absorption peaks coincide with those apparent in photoluminescence spectra. (Sb,As) intermixing with an antimony diffusion length of about 1 nm is found to make an important contribution to the observed transition energies. Dipole layer formation and quantum dot state filling contribute to the luminescence blueshift with increasing excitation density. The recombination rate of electrons with localized holes drastically depends on the average carrier density. When several carriers are localized at each dot, decay time constants around 5 ns, quite similar to type-I systems, are observed. Individual, spatially indirect excitons decay with much larger time constants close to 1 mu s. The decay time of quantum dot luminescence is independent of the temperature in the measured range T less than or equal to 65 K as expected for zero-dimensional excitons. [S0163-1829(98)04907-8].