Abstract
Semiconductor quantum dots (QDs) acting as single-photon-emitters are potential building blocks for various applications in future quantum information technology. For such applications, a thorough understanding and precise control of charge states and capture/recombination dynamics of the QDs are vital. In this work, we study the dynamics of QDs spontaneously formed in GaNAsP nanowires, belonging to the dilute nitride material system. By using a random population model modified for these highly mismatched materials, we analyze the results from photoluminescence and photon correlation experiments and show a general trend of disparity in positive and negative trion populations and also a strong dependence of the capture/recombination dynamics and QD charge states on its surroundings. Specifically, we show that the presence of hole-trap defects in the proximity to some QDs facilitates formation of negative trions, which also causes a dramatic reduction of the neutral exciton lifetime. These findings underline the importance of proper understanding of the QD capture and recombination processes and demonstrate the possibility to use highly mismatched materials and defects for charge engineering of QDs.
Highlights
Bright semiconductor quantum dots (QDs) are, through their inherent highly efficient single-photon emission, one of the most promising building blocks for a wide range of novel optical devices [1], such as quantum logic gates [2,3], and optically controlled switches [4], which can be utilized in various quantum communications [5] and quantum computation schemes [6]
We investigate the second type of QDs, where besides the X and XX peaks a third (X*) peak is observed in cwμPL spectra acquired using varying excitation powers—see Fig. 2(a)
By employing cw and time-resolved μPL spectroscopy and photon correlation measurements, we show that two types of QDs with significantly different photoluminescence characteristics are spontaneously formed in dilute nitride GaNAsP NWs grown by molecular beam epitaxy (MBE)
Summary
Bright semiconductor quantum dots (QDs) are, through their inherent highly efficient single-photon emission, one of the most promising building blocks for a wide range of novel optical devices [1], such as quantum logic gates [2,3], and optically controlled switches [4], which can be utilized in various quantum communications [5] and quantum computation schemes [6]. For these applications, optimizing exciton generation and recombination dynamics of a QD and its surroundings are of vital importance.
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