Toward Discrete Axial p-n Junction Nanowire Light-Emitting Diodes Grown by Plasma-Assisted Molecular Beam Epitaxy

Author:

Brubaker, Matt D.  Blanchard, Paul T.  Schlager, John B.  Sanders, Aric W.  Herrero, Andrew M.  Roshko, Alexana  Duff, Shannon M.  Harvey, Todd E.  Bright, Victor M.  Sanford, Norman A.  Bertness, Kris A.  

Journal:

JOURNAL OF ELECTRONIC MATERIALS

Issue Date:

2013

Abstract(summary):

In this paper we investigate axial p-n junction GaN nanowires grown by plasma-assisted molecular beam epitaxy (MBE), with particular attention to the effect of Mg doping on the device characteristics of individual nanowire light-emitting diodes (LEDs). We observe that a significant fraction of single-nanowire LEDs produce measurable band-gap electroluminescence when a thin AlGaN electron blocking layer (EBL) is incorporated into the device structure near the junction. Similar devices with no EBL typically yield below-detection-limit electroluminescence, despite diode-like I-V characteristics and optically measured internal quantum efficiencies (IQEs) of similar to 1%. I-V measurements of the p-regions in p-n junction nanowires, as well as nanowires doped with Mg only, indicate low p-type conductivity and asymmetric Schottky-like p-contacts. These observations suggest that imbalanced carrier injection from the junction and p-contact can produce significant nonradiative losses.

Page:

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