Profiling the local carrier concentration across a semiconductor quantum dot

Journal Article · Mon May 11 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4919919· OSTI ID:22399038

Walrath, J. C.; Lin, Yen-Hsiang ^[1]; Huang, S. ^[2]

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1. Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
2. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

We profile the local carrier concentration, n, across epitaxial InAs/GaAs quantum dots (QDs) consisting of 3D islands on top of a 2D alloy layer. We use scanning thermoelectric microscopy to measure a profile of the temperature gradient-induced voltage, which is converted to a profile of the local Seebeck coefficient, S. The S profile is then converted to a conduction band-edge profile and compared with Poisson-Schrodinger band-edge simulations. Our combined computational-experimental approach suggests a reduced carrier concentration in the QD center in comparison to that of the 2D alloy layer. The relative roles of free carrier trapping and/or dopant expulsion are discussed.

• OSTI ID: 22399038
• Journal Information: Applied Physics Letters, Vol. 106, Issue 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
CHARGE CARRIERS
COMPARATIVE EVALUATIONS
CONCENTRATION RATIO
ELECTRIC POTENTIAL
ELECTRONIC STRUCTURE
EPITAXY
GALLIUM ARSENIDES
INDIUM ARSENIDES
LAYERS
MICROSCOPY
QUANTUM DOTS
SEEBECK EFFECT
SEMICONDUCTOR MATERIALS
TEMPERATURE GRADIENTS
TRAPPING