4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=10&confId=86">The Proceedings of SAIP2016</a> published on 24 December 2017

Deep Level Transient Spectroscopy of GaSb/GaAs Quantum Dots

5 Jul 2016, 11:50
20m
4B (Kramer Law building)

4B

Kramer Law building

UCT Middle Campus Cape Town
Oral Presentation Track A - Division for Physics of Condensed Matter and Materials Division for Physics of Condensed Matter and Materials (2)

Speaker

Ms Danielle Venter (Nelson Mandela Metropolitan University)

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes

Please indicate whether<br>this abstract may be<br>published online<br>(Yes / No)

Yes

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

Self-assembled quantum dots (QDs) are interesting not only for studying charge confinement in zero dimensional systems, but also for the potential it offers towards the development of opto-electronic devices. In particular, GaSb/GaAs QD structures exhibit type-II band alignment in which the holes are strongly confined while a conduction band off-set creates a barrier to the flow of electrons. This, combined with the special separation between electrons and holes results in enhanced exciton lifetimes and reduced recombination probabilities, rendering these structures particularly suitable for long wavelength opto-electronic and memory device applications [1,2]. However, a thorough understanding of the electrical properties and carrier dynamics of these QD systems is an essential prerequisite for the development of the aforementioned mentioned devices.

In this study, the electronic properties of a GaSb/GaAs QD system, grown by molecular beam epitaxy, are investigated by means of current-voltage (IV), capacitance-voltage (CV) and Laplace deep level transient spectroscopy (L-DLTS). The IV measurements show a significant rectification (~ 4 orders of magnitude) between -1V and +1V with an ideality factor of 1.75 at 300 K. The reverse bias current of roughly 7nA displays a weak bias dependence up to -3V. Three prominent defects are detected around 140 K, 300 K and 330 K using a rate window of 200 Hz. L-DLTS is used to evaluate the defects around the QDs. The respective signatures and charge carrier dynamics are presented.

[1]. M. Hayne, J. Maes, S. Bersier, Appl. Phys.Lett. 82 (2003) 4355-4357.
[2]. M. Geller, C Kapteyn, L. Muller-Kirsch, R. Heitz, D. Blumberg, Appl. Phys. Lett. 82 (2003), 2706-2708

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

Yes

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD, N/A)?

MSc

Main supervisor (name and email)<br>and his / her institution

Prof Andre Venter
Andre.Venter@nmmu.ac.za
NMMU

Primary author

Ms Danielle Venter (Nelson Mandela Metropolitan University)

Co-authors

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