Time-resolved cathodoluminescence investigations of AlN:Ge/GaN nanowire structures

authored by: Jörgen Jungclaus, Hendrik Spende, Pascal Hille, Jörg Schörmann, Andreas Waag, Martin Eickhoff, Tobias Voss
Abstract: Light emitting diodes represent a key technology that can be found in many areas of everydays life. Therefore, the improvement of the efficiency of such structures offers a high economic and ecological potential. One approach is electrostatic screening of the quantum-confined Stark effect (QCSE) in polar III-V heterostructures by n-type doping in order to increase the oscillator strength of electronic transitions in quantum structures. In this study, we analyzed the cathodoluminescene (CL) spectra of different functional parts of individual AlN/GaN nanowire superlattices and studied their decay characteristics with sub-nanosecond time resolution. This allows us to extract information about strain and electric fields in such heterostructures with an overall spatial resolution <100 nm. The samples, which were investigated in a temperature range from 10 to 300 K by using time-integrated cathodoluminescence spectroscopy (TICL) and time-resolved cathodoluminescence spectroscopy (TRCL) consist of GaN bottom and top layer and a 40-fold stack of GaN nanodiscs, embedded in AlN barriers that were doped with Ge. We show, that the QCSE is reduced with increasing doping concentration due to a screening of the internal electric fields inside GaN nanodiscs, resulting in a reduction of the carrier lifetimes and a blue shift of the emitted light. Due to the small diameter of the electron excitation beam CL offers the possibility to individually analyze the different functional parts of the nanowires.
External Organisation(s): Technische Universität Braunschweig
University of Bremen
Justus Liebig University Giessen
Type: Article
Journal: Nano Express
Volume: 2
ISSN: 2632-959X
Publication date: 13.07.2021
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Polymers and Plastics, Biomaterials, Materials Science (miscellaneous)
Electronic version(s): https://doi.org/10.1088/2632-959x/ac0598 (Access: Open)

BibTeX

@article{24d8b42cdf2c469c9c7511d91d5ece8c,
title = "Time-resolved cathodoluminescence investigations of AlN:Ge/GaN nanowire structures",
abstract = "Light emitting diodes represent a key technology that can be found in many areas of everydays life. Therefore, the improvement of the efficiency of such structures offers a high economic and ecological potential. One approach is electrostatic screening of the quantum-confined Stark effect (QCSE) in polar III-V heterostructures by n-type doping in order to increase the oscillator strength of electronic transitions in quantum structures. In this study, we analyzed the cathodoluminescene (CL) spectra of different functional parts of individual AlN/GaN nanowire superlattices and studied their decay characteristics with sub-nanosecond time resolution. This allows us to extract information about strain and electric fields in such heterostructures with an overall spatial resolution <100 nm. The samples, which were investigated in a temperature range from 10 to 300 K by using time-integrated cathodoluminescence spectroscopy (TICL) and time-resolved cathodoluminescence spectroscopy (TRCL) consist of GaN bottom and top layer and a 40-fold stack of GaN nanodiscs, embedded in AlN barriers that were doped with Ge. We show, that the QCSE is reduced with increasing doping concentration due to a screening of the internal electric fields inside GaN nanodiscs, resulting in a reduction of the carrier lifetimes and a blue shift of the emitted light. Due to the small diameter of the electron excitation beam CL offers the possibility to individually analyze the different functional parts of the nanowires.",
keywords = "AlN/GaN nanowire structures, cathodoluminescence, doped nanowires, GaN nanowires, nanowires, quantum-confined Stark effect, time-resolved cathodoluminescence",
author = "J{\"o}rgen Jungclaus and Hendrik Spende and Pascal Hille and J{\"o}rg Sch{\"o}rmann and Andreas Waag and Martin Eickhoff and Tobias Voss",
note = "Publisher Copyright: {\textcopyright} 2021 The Author(s). Published by IOP Publishing Ltd.",
year = "2021",
month = jul,
day = "13",
doi = "10.1088/2632-959x/ac0598",
language = "English",
volume = "2",
journal = "Nano Express",
issn = "2632-959X",
publisher = "IOP Publishing Ltd.",
number = "3",
}