Issue 20, 2023

Physical probing of quantum energy levels in a single indium arsenide (InAs) quantum dot

Abstract

Indium arsenide (InAs) quantum dots (QDs) grown by molecular beam epitaxy (EBM) on gallium arsenide (GaAs) substrates have exhibited quantized charge-trapping characteristics. An electric charge can be injected in a single QD by a gold-coated AFM nano-probe placed directly on it using a conductive-mode atomic force microscope (C-AFM). The results revealed separate current–voltage (IV) curves during consecutive measurements, where the turn-on voltages measured at the subsequent voltage sweeps are incrementally lower than that at the initial sweep. We demonstrate that the charge state of the QD can change over a long enough time by measuring the IV data on the same QD at different time intervals. Discrete energy states (here, five states) have been observed due to the quantized charge leakage from the QD into the surrounding materials. These quantum states with five energy levels have been verified using quantum theory analysis of the quantum-well with the help of a numerical simulation model, which depends on the QD dimensions. The size of the quantum-well in the model is in good agreement with the actual QD size, whose lateral dimension is confirmed using a scanning electron microscope. At the same time, the height is estimated from the atomic force microscope topography.

Graphical abstract: Physical probing of quantum energy levels in a single indium arsenide (InAs) quantum dot

Associated articles

Article information

Article type
Paper
Submitted
12 Aug 2023
Accepted
15 Sep 2023
First published
18 Sep 2023
This article is Open Access
Creative Commons BY-NC license

Nanoscale Adv., 2023,5, 5562-5569

Physical probing of quantum energy levels in a single indium arsenide (InAs) quantum dot

M. Rezeq, Y. Abbas, B. Wen, Z. Wasilewski and D. Ban, Nanoscale Adv., 2023, 5, 5562 DOI: 10.1039/D3NA00638G

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