Ultra-shallow quantum dots in an undoped GaAs/AlGaAs two-dimensional electron gas
Ultra-shallow quantum dots in an undoped GaAs/AlGaAs two-dimensional electron gas
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DOI：
10.1063/1.4795613
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发表时间：
2011-12
影响因子：
4
通讯作者：
W. Y. Mak;F. Sfigakis;K. D. Gupta;O. Klochan;H. Beere;I. Farrer;J. Griffiths;G. Jones;A. Hamilton;D. Ritchie
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文献类型：
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作者：
W. Y. Mak;F. Sfigakis;K. D. Gupta;O. Klochan;H. Beere;I. Farrer;J. Griffiths;G. Jones;A. Hamilton;D. Ritchie
我们报道了在分子束外延生长的未掺杂GaAs/AlGaAs异质结中，在表面以下仅30 nm的非常浅的二维电子气上制备的量子点。由于没有掺杂剂，相对于具有类似深度的掺杂异质结构，观察到迁移率（在2 × 1011 cm-2处）的一个数量级以上的改善。这些未掺杂的晶片可以很容易地被门控与表面金属栅极图案化的电子束光刻，如这里所示，从单级传输通过量子点显示大的充电能量（高达1.75毫电子伏）和激发态能量（高达0.5毫电子伏）。
We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy. Due to the absence of dopants, an improvement of more than one order of magnitude in mobility (at 2 × 1011 cm−2) with respect to doped heterostructures with similar depths is observed. These undoped wafers can easily be gated with surface metallic gates patterned by e-beam lithography, as demonstrated here from single-level transport through a quantum dot showing large charging energies (up to 1.75 meV) and excited state energies (up to 0.5 meV).