Experimental Detection and Control of Trions and Fermi-Edge Singularity in Single-Barrier GaAs/AlAs/GaAs Heterostructures Using Photocapacitance Spectroscopy

Bhunia, Amit; Singh, Mohit Kumar; Gobato, Y. Galv�o; Henini, Mohamed; Datta, Shouvik

Abstract

© 2018 American Physical Society. We show how photocapacitance spectra can probe and manipulate two dimensional excitonic complexes and Fermi-edge singularities as a function of applied bias even at a temperature of 100 K. For lower density regimes (1×1011cm-2), we observe a sharp spectral transition from trions to asymmetrically shaped Fermi-edge singularities in photocapacitance spectra above a particular reverse bias. However, these signatures of indirect excitonic states are absent from photoluminescence spectra. Such dissimilarities clearly point out that different many body physics govern these two spectral measurements. We also argue why such quantum-confined dipoles of spatially indirect trions can have thermodynamically finite probability to survive even around 100 K. Finally, our observations demonstrate that photocapacitance spectroscopy, which was rarely used to detect trions in the past, can also be useful to detect the traces of these spatially indirect excitonic complexes as well as Fermi-edge singularities. This is mainly due to the enhanced sensitivity of these capacitive measurements to "dipolar" changes of excitonic complexes in these heterojunctions. Thus, our studies clearly open up future possibilities for electro-optical modulation and detection of trions and Fermi-edge singularities in several other heterostructures for next-generation optoelectronic applications.

Citation

Bhunia, A., Singh, M. K., Gobato, Y. G., Henini, M., & Datta, S. (2018). Experimental Detection and Control of Trions and Fermi-Edge Singularity in Single-Barrier GaAs/AlAs/GaAs Heterostructures Using Photocapacitance Spectroscopy. Physical Review Applied, 10(4), Article 044043. https://doi.org/10.1103/physrevapplied.10.044043

• Journal Article Type: Article
• Acceptance Date: Jul 9, 2018
• Online Publication Date: Oct 17, 2018
• Publication Date: Oct 17, 2018
• Deposit Date: Oct 20, 2018
• Publicly Available Date: Oct 22, 2018
• Journal: Physical Review Applied
• Electronic ISSN: 2331-7019
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Issue: 4
• Article Number: 044043
• DOI: https://doi.org/10.1103/physrevapplied.10.044043
• Public URL: https://nottingham-repository.worktribe.com/output/1177478
• Publisher URL: https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.10.044043
• Additional Information: ©2018 American Physical Society
• Contract Date: Oct 22, 2018