Details
| Original language | English |
|---|---|
| Article number | 034001 |
| Journal | Nano Express |
| Volume | 2 |
| Issue number | 3 |
| Publication status | Published - 13 Jul 2021 |
| Externally published | Yes |
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
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Materials Science(all)
- Polymers and Plastics
- Materials Science(all)
- Biomaterials
- Materials Science(all)
- Materials Science (miscellaneous)
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In: Nano Express, Vol. 2, No. 3, 034001, 13.07.2021.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Time-resolved cathodoluminescence investigations of AlN:Ge/GaN nanowire structures
AU - Jungclaus, Jörgen
AU - Spende, Hendrik
AU - Hille, Pascal
AU - Schörmann, Jörg
AU - Waag, Andreas
AU - Eickhoff, Martin
AU - Voss, Tobias
N1 - Publisher Copyright: © 2021 The Author(s). Published by IOP Publishing Ltd.
PY - 2021/7/13
Y1 - 2021/7/13
N2 - 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.
AB - 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.
KW - AlN/GaN nanowire structures
KW - cathodoluminescence
KW - doped nanowires
KW - GaN nanowires
KW - nanowires
KW - quantum-confined Stark effect
KW - time-resolved cathodoluminescence
UR - http://www.scopus.com/inward/record.url?scp=85129084547&partnerID=8YFLogxK
U2 - 10.1088/2632-959x/ac0598
DO - 10.1088/2632-959x/ac0598
M3 - Article
VL - 2
JO - Nano Express
JF - Nano Express
SN - 2632-959X
IS - 3
M1 - 034001
ER -