Quantifying the Transverse-Electric-Dominant 260 nm Emission from Molecular Beam Epitaxy-Grown GaN-Quantum-Disks Embedded in AlN Nanowires: A Comprehensive Optical and Morphological Characterization
| Autor: | Ursel Bangert, Ram Chandra Subedi, Iman S. Roqan, Jung-Wook Min, Boon S. Ooi, Kuang-Hui Li, Kalani Moore, Somak Mitra, Michele Conroy, Dalaver H. Anjum, Edgars Stegenburgs, Tien Khee Ng, Idris A. Ajia |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Photoluminescence Materials science business.industry Nanowire 02 engineering and technology 021001 nanoscience & nanotechnology Epitaxy 01 natural sciences Semiconductor Quantum dot 0103 physical sciences Scanning transmission electron microscopy Optoelectronics General Materials Science Quantum efficiency 0210 nano-technology business Molecular beam epitaxy |
| Zdroj: | ACS Applied Materials & Interfaces. 12:41649-41658 |
| ISSN: | 1944-8252 1944-8244 |
| Popis: | There has been a relentless pursuit of transverse electric (TE)-dominant deep ultraviolet (UV) optoelectronic devices for efficient surface emitters to replace the environmentally unfriendly mercury lamps. To date, the use of the ternary AlGaN alloy inevitably has led to transverse magnetic (TM)-dominant emission, an approach that is facing a roadblock. Here, we take an entirely different approach of utilizing a binary GaN compound semiconductor in conjunction with ultrathin quantum disks (QDisks) embedded in AlN nanowires (NWs). The growth of GaN QDisks is realized on a scalable and low-cost Si substrate using plasma-assisted molecular beam epitaxy as a highly controllable monolayer growth platform. We estimated an internal quantum efficiency of ∼81% in a wavelength regime of ∼260 nm for these nanostructures. Additionally, strain mapping obtained by high-angle annular dark-field scanning transmission electron microscopy is studied in conjunction with the TE and TM modes of the carrier recombination. Moreover, for the first time, we quantify the TE and TM modes of the PL emitted by GaN QDisks for deep-UV emitters. We observed nearly pure TE-polarized photoluminescence emission at a polarization angle of ∼5°. This work proposes highly quantum-confined ultrathin GaN QDisks as a promising candidate for deep-UV vertical emitters. |
| Databáze: | OpenAIRE |
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