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Johar MA, Song HG, Waseem A, Kang JH, Ha JS, Cho YH, Ryu SW. Ultrafast carrier dynamics of conformally grown semi-polar (112[combining macron]2) GaN/InGaN multiple quantum well co-axial nanowires on m-axial GaN core nanowires. NANOSCALE 2019; 11:10932-10943. [PMID: 31139802 DOI: 10.1039/c9nr02823d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The growth of semi-polar (112[combining macron]2) GaN/InGaN multiple-quantum-well (MQW) co-axial heterostructure shells around m-axial GaN core nanowires on a Si substrate using MOCVD is reported for the first time. The core GaN nanowire and GaN/InGaN MQW shells are grown in a two-step growth sequence of vapor-liquid-solid and vapor-solid growth modes. The luminescence and carrier dynamics of GaN/InGaN MQW coaxial nanowires are studied by photoluminescence, cathodoluminescence, and low temperature time-resolved photoluminescence (TRPL). The emission is tuned from 430 nm to 590 nm by increasing the InGaN QW thickness. The non-single exponential decay measured by low-temperature TRPL was attributed to the indium fluctuations in the InGaN QW. The ultrafast radiative lifetime was measured from 14 ps to 26 ps with different emission wavelengths at a very high internal quantum efficiency up to 68%. An ultrafast carrier lifetime was assigned to the growth of the InGaN QW on semi-polar (112[combining macron]2) growth facet and the improved carrier collection efficiency due to the radial growth of the GaN/InGaN MQW shells. Such an ultrafast carrier dynamics of NWs provides a meaningful active medium for high speed optoelectronic applications.
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Affiliation(s)
- Muhammad Ali Johar
- Department of Physics, Chonnam National University, Gwangju 61186, Republic of Korea.
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Ilyas N, Li D, Song Y, Zhong H, Jiang Y, Li W. Low-Dimensional Materials and State-of-the-Art Architectures for Infrared Photodetection. SENSORS (BASEL, SWITZERLAND) 2018; 18:E4163. [PMID: 30486432 PMCID: PMC6308609 DOI: 10.3390/s18124163] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 12/13/2022]
Abstract
Infrared photodetectors are gaining remarkable interest due to their widespread civil and military applications. Low-dimensional materials such as quantum dots, nanowires, and two-dimensional nanolayers are extensively employed for detecting ultraviolet to infrared lights. Moreover, in conjunction with plasmonic nanostructures and plasmonic waveguides, they exhibit appealing performance for practical applications, including sub-wavelength photon confinement, high response time, and functionalities. In this review, we have discussed recent advances and challenges in the prospective infrared photodetectors fabricated by low-dimensional nanostructured materials. In general, this review systematically summarizes the state-of-the-art device architectures, major developments, and future trends in infrared photodetection.
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Affiliation(s)
- Nasir Ilyas
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Dongyang Li
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Yuhao Song
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Hao Zhong
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Yadong Jiang
- School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
| | - Wei Li
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China.
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Adhikari A, Eliason JK, Sun J, Bose R, Flannigan DJ, Mohammed OF. Four-Dimensional Ultrafast Electron Microscopy: Insights into an Emerging Technique. ACS APPLIED MATERIALS & INTERFACES 2017; 9:3-16. [PMID: 27976852 DOI: 10.1021/acsami.6b12301] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Four-dimensional ultrafast electron microscopy (4D-UEM) is a novel analytical technique that aims to fulfill the long-held dream of researchers to investigate materials at extremely short spatial and temporal resolutions by integrating the excellent spatial resolution of electron microscopes with the temporal resolution of ultrafast femtosecond laser-based spectroscopy. The ingenious use of pulsed photoelectrons to probe surfaces and volumes of materials enables time-resolved snapshots of the dynamics to be captured in a way hitherto impossible by other conventional techniques. The flexibility of 4D-UEM lies in the fact that it can be used in both the scanning (S-UEM) and transmission (UEM) modes depending upon the type of electron microscope involved. While UEM can be employed to monitor elementary structural changes and phase transitions in samples using real-space mapping, diffraction, electron energy-loss spectroscopy, and tomography, S-UEM is well suited to map ultrafast dynamical events on materials surfaces in space and time. This review provides an overview of the unique features that distinguish these techniques and also illustrates the applications of both S-UEM and UEM to a multitude of problems relevant to materials science and chemistry.
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Affiliation(s)
- Aniruddha Adhikari
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Jeffrey K Eliason
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Jingya Sun
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Riya Bose
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Omar F Mohammed
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
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Khan JI, Adhikari A, Sun J, Priante D, Bose R, Shaheen BS, Ng TK, Zhao C, Bakr OM, Ooi BS, Mohammed OF. Enhanced Optoelectronic Performance of a Passivated Nanowire-Based Device: Key Information from Real-Space Imaging Using 4D Electron Microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:2313-2320. [PMID: 26938476 DOI: 10.1002/smll.201503651] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/03/2016] [Indexed: 06/05/2023]
Abstract
Managing trap states and understanding their role in ultrafast charge-carrier dynamics, particularly at surface and interfaces, remains a major bottleneck preventing further advancements and commercial exploitation of nanowire (NW)-based devices. A key challenge is to selectively map such ultrafast dynamical processes on the surfaces of NWs, a capability so far out of reach of time-resolved laser techniques. Selective mapping of surface dynamics in real space and time can only be achieved by applying four-dimensional scanning ultrafast electron microscopy (4D S-UEM). Charge carrier dynamics are spatially and temporally visualized on the surface of InGaN NW arrays before and after surface passivation with octadecylthiol (ODT). The time-resolved secondary electron images clearly demonstrate that carrier recombination on the NW surface is significantly slowed down after ODT treatment. This observation is fully supported by enhancement of the performance of the light emitting device. Direct observation of surface dynamics provides a profound understanding of the photophysical mechanisms on materials' surfaces and enables the formulation of effective surface trap state management strategies for the next generation of high-performance NW-based optoelectronic devices.
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Affiliation(s)
- Jafar I Khan
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Aniruddha Adhikari
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Jingya Sun
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Davide Priante
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Riya Bose
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Basamat S Shaheen
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Tien Khee Ng
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Chao Zhao
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Osman M Bakr
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Boon S Ooi
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Omar F Mohammed
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
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