Surface defects of silicon quantum dots are responsible for energy levels inside the fundamental gap, trapping charge carriers in electronic devices. Employing <i>ab initio</i> calculations with constrained density functional theory, we examine the effect of deep and shallow defect energy levels on charge transport in quantum dot arrays. Surprisingly, we found that shallow defect energy levels may be more detrimental to charge transport than deep defect energy levels, resulting in electron capture rates which differ by up to 5 orders of magnitude for the small dots (1-2 nm) we considered. Our results challenge the assumption that charge carrier traps are solely defined by their position within the energy gap, suggesting that experimental efforts may need to focus on resolving shallow defects as well. Our investigation highlights the need to consider atomistic detail in modeling the charge transport of quantum dot arrays.

<i>Ab initio</i> modeling of charge transport defects in quantum dot arrays

253rd National Meeting (2017)

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Ab initio modeling of charge transport defects in quantum dot arrays