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

Bhunia, Amit; Singh, Mohit Kumar; Galvao Gobato, Y.; Henini, M.; Datta, Shouvik

Authors

Amit Bhunia

Mohit Kumar Singh

Y. Galvao Gobato

Shouvik Datta



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.

Journal Article Type Article
Journal Journal of Applied Physics
Print ISSN 0021-8979
Electronic ISSN 1089-7550
Publisher AIP Publishing
Peer Reviewed Peer Reviewed
Volume 123
Issue 4
Article Number 044305
APA6 Citation Bhunia, A., Singh, M. K., Galvao Gobato, Y., Henini, M., & Datta, S. (in press). 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(4), https://doi.org/10.1063/1.5007820
DOI https://doi.org/10.1063/1.5007820
Publisher URL http://aip.scitation.org/doi/10.1063/1.5007820
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf
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

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://eprints.nottingham.ac.uk/end_user_agreement.pdf





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