Direct bandgap narrowing in Ge LED's on Si substrates

Oehme M, Gollhofer M, Widmann D, Schmid M, Kaschel M, Kasper E, Schulze J (2013)

Publication Type: Journal article

Publication year: 2013

Journal

Optics Express Optical Society of America

Book Volume: 21

Pages Range: 2206-2211

Journal Issue: 2

DOI: 10.1364/OE.21.002206

Abstract

In this paper we investigate the influence of n-type doping in Ge light emitting diodes on Si substrates on the room temperature emission spectrum. The layer structures are grown with a special low temperature molecular beam epitaxy process resulting in a slight tensile strain of 0.13%. The Ge LED's show a dominant direct bandgap emission with shrinking bandgap at the Γ point in dependence of n-type doping level. The emission shift (38 meV at 10²⁰ cm^-3) is mainly assigned to bandgap narrowing at high doping. The electroluminescence intensity increases with doping concentrations up to 3×10¹⁹ cm^-3 and decreases sharply at higher doping levels. The integrated direct gap emission intensity increases superlinear with electrical current density. Power exponents vary from about 2 at low doping densities up to 3.6 at 10²⁰ cm^-3 doping density. © 2013 Optical Society of America.

Authors with CRIS profile

Jörg Schulze

Involved external institutions

Universität Stuttgart

Germany (DE)

How to cite

APA:

Oehme, M., Gollhofer, M., Widmann, D., Schmid, M., Kaschel, M., Kasper, E., & Schulze, J. (2013). Direct bandgap narrowing in Ge LED's on Si substrates. Optics Express, 21(2), 2206-2211. https://doi.org/10.1364/OE.21.002206

MLA:

Oehme, Michael, et al. "Direct bandgap narrowing in Ge LED's on Si substrates." Optics Express 21.2 (2013): 2206-2211.

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