Experimental evidences of quantum confined 2D indirect excitons in single barrier GaAs/AlAs/GaAs heterostructure using photocapacitance at room temperature

Bhunia, Amit and Singh, Mohit Kumar and Galvao Gobato, Y. and Henini, M. and Datta, Shouvik (2018) Experimental evidences of quantum confined 2D indirect excitons in single barrier GaAs/AlAs/GaAs heterostructure using photocapacitance at room temperature. Journal of Applied Physics, 123 . 044305-1-044305-8. ISSN 1089-7550

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Abstract

We investigated excitonic absorptions in a GaAs/AlAs/GaAs single barrier heterostructure using both photocapacitance and photocurrent spectroscopies at room temperature. Photocapacitance spectra show well defined resonance peaks of indirect excitons formed around the C-AlAs barrier. Unlike DC-photocurrent spectra, frequency dependent photocapacitance spectra interestingly red shift, sharpen up, and then decrease with increasing tunneling at higher biases. Such dissimilarities clearly point out that different exciton dynamics govern these two spectral measurements. We also argue why such quantum confined dipoles of indirect excitons can have thermodynamically finite probabilities to survive even at room temperature. Finally, our observations demonstrate that the photocapacitance technique, which was seldom used to detect excitons in the past, is useful for selective detection and experimental tuning of relatively small numbers ( 1011/cm2) of photo-generated indirect excitons having large effective dipole moments in this type of quasi-two dimensional heterostructures.

Item Type: Article
Additional Information: This is an author's accepted manuscript of the following article: Bhunia, Amit; Singh, Mohit Kumar; Galvao Gobato, Y.; Henini, Mohamed; Datta, Shouvik. Experimental evidences of quantum confined 2D indirect excitons in single barrier GaAs/AlAs/GaAs heterostructure using photocapacitance at room temperature. Journal of Applied Physics. Journal of Applied Physics 123, 044305 (2018) published by the American Institute of Physics and available online https://doi.org/10.1063/1.5007820
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1063/1.5007820
Depositing User: Henini, Mohamed
Date Deposited: 02 Feb 2018 09:10
Last Modified: 02 Feb 2018 09:18
URI: http://eprints.nottingham.ac.uk/id/eprint/49487

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