Deep traps in GaAs/InGaAs quantum wells and quantum dots, studied by noise spectroscopy

Journal Article · Sat Nov 15 00:00:00 EST 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3020532· OSTI ID:21185925

Kunets, Vas P; Morgan, T Al; Mazur, Yu I; Dorogan, V G; Lytvyn, P M; Ware, M E; Guzun, D; Shultz, J L; Salamo, G J ^[1]

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1. Arkansas Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

Remotely doped In{sub 0.35}Ga{sub 0.65}As layers of different coverages 6, 9, 11, and 13 ML were grown by molecular beam epitaxy on (100) GaAs. Quantum dot (QD) nucleation was observed in situ by reflection high-energy electron diffraction at 8 ML growth of In{sub 0.35}Ga{sub 0.65}As, while for 6 ML, only two-dimensional (2D) growth was observed. Atomic force microscopy, low temperature photoluminescence, and Hall effect measurements confirmed this transition from 2D to three-dimensional growth. Low-frequency noise studies have been performed to probe defects in such heterostructures throughout the transition from a highly strained quantum well to QDs. Results were compared to a bulk n-type GaAs reference sample. We revealed three main defects in GaAs with activation energies of 0.8, 0.54, and 0.35 eV. These defects with the same activation energies were found in all samples. However, structures containing In{sub 0.35}Ga{sub 0.65}As QDs show an additional peak at low temperatures due to the presence of defects which are not observed for reference GaAs and quantum well samples. Detailed analysis shows that for 9 and 11 ML In{sub 0.35}Ga{sub 0.65}As QD samples this peak corresponds to the well known M1 defect in GaAs with an activation energy of 0.18 eV, while for a coverage of 13 ML the defect was found to have an activation energy of 0.12 eV. All defects were characterized quantitatively in terms of their activation energy, capture cross section, and density. These studies indicate that noise spectroscopy is a very sensitive tool for electronic material characterization on the nanoscale.

• OSTI ID: 21185925
• Journal Information: Journal of Applied Physics, Vol. 104, Issue 10; Other Information: DOI: 10.1063/1.3020532; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
ATOMIC FORCE MICROSCOPY
CROSS SECTIONS
CRYSTAL DEFECTS
CRYSTAL GROWTH
DOPED MATERIALS
ELECTRON DIFFRACTION
GALLIUM ARSENIDES
HALL EFFECT
HETEROJUNCTIONS
INDIUM ARSENIDES
MOLECULAR BEAM EPITAXY
NUCLEATION
PHOTOLUMINESCENCE
QUANTUM DOTS
QUANTUM WELLS
SEMICONDUCTOR MATERIALS
SPECTROSCOPY
THREE-DIMENSIONAL CALCULATIONS
TWO-DIMENSIONAL CALCULATIONS