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Liu S, Zhang L, Ma B, Zeng X, Liu Y, Ma Z, Yang Z, Wang X. High-Performance Ultraviolet to Near-Infrared Antiambipolar Photodetectors Based on 1D CdS xSe 1-x/2D Te Heterojunction. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39222360 DOI: 10.1021/acsami.4c05528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Antiambipolar heterojunctions are regarded as a revolutionary technology in the fields of electronics and optoelectronics, enabling the switch between positive and negative transconductance within a single device, which is crucial for diverse logic circuit applications. This study pioneers a mixed-dimensional photodetector featuring antiambipolar properties, facilitated by the van der Waals integration of one-dimensional CdSxSe1-x nanowires and two-dimensional Te nanosheets. This antiambipolar device enables flexible control over carrier transport via gate voltage, thus paving new paths for future optoelectronic devices. Furthermore, by precisely managing the stoichiometry of the ternary alloy CdSxSe1-x nanowires, fine-tuning of the nanowire band structure is achieved. This allows for customizable heterojunction band alignment (Type I and Type II), enabling adjustable band alignment. Through sophisticated band engineering, optimal Type II band alignment is achieved at the CdSxSe1-x/Te interface, significantly enhancing the device's photoelectric conversion efficiency through the synergistic effect of different dimensional materials. Exhibiting outstanding photoresponse across a broad spectral range from ultraviolet to near-infrared, especially under 450 nm illumination, the CdSxSe1-x/Te heterojunction photodetector demonstrates superior performance, including an impressive responsivity of 284 A W-1, a high detectivity of 1.07 × 1017 Jones, an elevated external quantum efficiency of 7.83 × 104 %, and a swift response time of 11 μs. Ultimately, this customizable antiambipolar photodetector lays a solid foundation for the advancement of next-generation optoelectronic technologies.
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Affiliation(s)
- Shuo Liu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Liang Zhang
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
- Research Center for Novel Computational Sensing and Intelligent Processing, Zhejiang Laboratory, Hangzhou, Zhejiang 311100, China
| | - Boyang Ma
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiangyu Zeng
- Hangzhou Institute of Technology, Xidian University, Hangzhou 311200, China
| | - Yang Liu
- Department of Physics, Loughborough University, Loughborough LE11 3TU, U.K
| | - Zhi Ma
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zongyin Yang
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiaozhi Wang
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
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Wach Q, Quick MT, Ayari S, Achtstein AW. Field-dependent THz transport nonlinearities in semiconductor nano structures. Phys Chem Chem Phys 2024; 26:13995-14005. [PMID: 38683165 DOI: 10.1039/d4cp00952e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Charge transport nonlinearities in semiconductor quantum dots and nanorods are studied. Using a density matrix formalism, we retrieve the field-dependent nonlinear mobility and show the possibility of intra-pulse gain. We further demonstrate that the dynamics of master equations can be captured in an analytical formula for the field-dependent charge carrier mobility, e.g. for two-level systems. This equation extends the linear response theory based Kubo-Greenwood result to nonlinear processes at elevated field strength, easily reached in THz transport spectroscopy. With these tools we analyze the field strength, chirp, temperature and dephasing dependence of the charge carrier mobility in the model system of CdSe quantum dots and wires. Stark broadening and Rabi splitting result in strong alterations of the mobility spectra, pronounced at low temperatures. The mobility spectra are strongly temperature and pulse shape dependent in the nonlinear regime. The findings are of immediate interest e.g. for nonlinear THz generation, conversion and amplification in 6G technology and nano electronics. Our results further enable experimentalists to fit and understand measured charge transport nonlinearities with analytical expressions and to design nanosystems with engineered material properties.
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Affiliation(s)
- Quentin Wach
- Institute of Optics and Atomic Physics, Technische Universität Berlin, 10623 Berlin, Germany
| | - Michael T Quick
- Institute of Optics and Atomic Physics, Technische Universität Berlin, 10623 Berlin, Germany
| | - Sabrine Ayari
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Alexander W Achtstein
- Institute of Optics and Atomic Physics, Technische Universität Berlin, 10623 Berlin, Germany
- Fakultät für Physik, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany.
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3
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Yuan L, Pokharel R, Devkota S, Kuchoor H, Dawkins K, Lee MC, Huang Y, Yarotski D, Iyer S, Prasankumar RP. Revealing charge carrier dynamics and transport in Te-doped GaAsSb and GaAsSbN nanowires by correlating ultrafast terahertz spectroscopy and optoelectronic characterization. NANOTECHNOLOGY 2022; 33:425702. [PMID: 35772308 DOI: 10.1088/1361-6528/ac7d61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Recent advances in the growth of III-V semiconductor nanowires (NWs) hold great promise for nanoscale optoelectronic device applications. It is established that a small amount of nitrogen (N) incorporation in III-V semiconductor NWs can effectively red-shift their wavelength of operation and tailor their electronic properties for specific applications. However, understanding the impact of N incorporation on non-equilibrium charge carrier dynamics and transport in semiconducting NWs is critical in achieving efficient semiconducting NW devices. In this work, ultrafast optical pump-terahertz probe spectroscopy has been used to study non-equilibrium carrier dynamics and transport in Te-doped GaAsSb and dilute nitride GaAsSbN NWs, with the goal of correlating these results with electrical characterization of their equilibrium photo-response under bias and low-frequency noise characteristics. Nitrogen incorporation in GaAsSb NWs led to a significant increase in the carrier scattering rate, resulting in a severe reduction in carrier mobility. Carrier recombination lifetimes of 33 ± 1 picoseconds (ps) and 147 ± 3 ps in GaAsSbN and GaAsSb NWs, respectively, were measured. The reduction in the carrier lifetime and photoinduced optical conductivities are due to the presence of N-induced defects, leading to deterioration in the electrical and optical characteristics of dilute nitride NWs relative to the non-nitride NWs. Finally, we observed a very fast rise time of ∼2 ps for both NW materials, directly impacting their potential use as high-speed photodetectors.
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Affiliation(s)
- Long Yuan
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Rabin Pokharel
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Shisir Devkota
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Hirandeep Kuchoor
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Kendall Dawkins
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Min-Cheol Lee
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Yue Huang
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Dzmitry Yarotski
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Shanthi Iyer
- Nanoengineering Department, Joint School of Nanoscience and Nanoengineering, North Carolina A&T University, Greensboro, NC 27401, United States of America
| | - Rohit P Prasankumar
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
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Alam KM, Jensen CE, Kumar P, Hooper RW, Bernard GM, Patidar A, Manuel AP, Amer N, Palmgren A, Purschke DN, Chaulagain N, Garcia J, Kirwin PS, Shoute LCT, Cui K, Gusarov S, Kobryn AE, Michaelis VK, Hegmann FA, Shankar K. Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C 3N 5 Core-Shell Nanowires. ACS APPLIED MATERIALS & INTERFACES 2021; 13:47418-47439. [PMID: 34608803 DOI: 10.1021/acsami.1c08550] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We present a potential solution to the problem of extraction of photogenerated holes from CdS nanocrystals and nanowires. The nanosheet form of C3N5 is a low-band-gap (Eg = 2.03 eV), azo-linked graphenic carbon nitride framework formed by the polymerization of melem hydrazine (MHP). C3N5 nanosheets were either wrapped around CdS nanorods (NRs) following the synthesis of pristine chalcogenide or intercalated among them by an in situ synthesis protocol to form two kinds of heterostructures, CdS-MHP and CdS-MHPINS, respectively. CdS-MHP improved the photocatalytic degradation rate of 4-nitrophenol by nearly an order of magnitude in comparison to bare CdS NRs. CdS-MHP also enhanced the sunlight-driven photocatalytic activity of bare CdS NWs for the decolorization of rhodamine B (RhB) by a remarkable 300% through the improved extraction and utilization of photogenerated holes due to surface passivation. More interestingly, CdS-MHP provided reaction pathway control over RhB degradation. In the absence of scavengers, CdS-MHP degraded RhB through the N-deethylation pathway. When either hole scavenger or electron scavenger was added to the RhB solution, the photocatalytic activity of CdS-MHP remained mostly unchanged, while the degradation mechanism shifted to the chromophore cleavage (cycloreversion) pathway. We investigated the optoelectronic properties of CdS-C3N5 heterojunctions using density functional theory (DFT) simulations, finite difference time domain (FDTD) simulations, time-resolved terahertz spectroscopy (TRTS), and photoconductivity measurements. TRTS indicated high carrier mobilities >450 cm2 V-1 s-1 and carrier relaxation times >60 ps for CdS-MHP, while CdS-MHPINS exhibited much lower mobilities <150 cm2 V-1 s-1 and short carrier relaxation times <20 ps. Hysteresis in the photoconductive J-V characteristics of CdS NWs disappeared in CdS-MHP, confirming surface passivation. Dispersion-corrected DFT simulations indicated a delocalized HOMO and a LUMO localized on C3N5 in CdS-MHP. C3N5, with its extended π-conjugation and low band gap, can function as a shuttle to extract carriers and excitons in nanostructured heterojunctions, and enhance performance in optoelectronic devices. Our results demonstrate how carrier dynamics in core-shell heterostructures can be manipulated to achieve control over the reaction mechanism in photocatalysis.
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Affiliation(s)
- Kazi M Alam
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
- Nanotechnology Research Centre, National Research Council Canada, Edmonton, Alberta T6G 2M9, Canada
| | - Charles E Jensen
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Pawan Kumar
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Riley W Hooper
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Guy M Bernard
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Aakash Patidar
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Ajay P Manuel
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Naaman Amer
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Anders Palmgren
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - David N Purschke
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Narendra Chaulagain
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - John Garcia
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Phillip S Kirwin
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Lian C T Shoute
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Kai Cui
- Nanotechnology Research Centre, National Research Council Canada, Edmonton, Alberta T6G 2M9, Canada
| | - Sergey Gusarov
- Nanotechnology Research Centre, National Research Council Canada, Edmonton, Alberta T6G 2M9, Canada
| | - Alexander E Kobryn
- Nanotechnology Research Centre, National Research Council Canada, Edmonton, Alberta T6G 2M9, Canada
| | - Vladimir K Michaelis
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Frank A Hegmann
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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Quick MT, Owschimikow N, Achtstein AW. Terahertz Charge Carrier Mobility in 1D and 2D Semiconductor Nanoparticles. J Phys Chem Lett 2021; 12:7688-7695. [PMID: 34378384 DOI: 10.1021/acs.jpclett.1c02045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We investigate the charge carrier mobility in 1D and 2D semiconductor nanoparticle domains with a focus on the interpretation of THz mobility measurements. We provide a microscopic understanding of the frequency-dependent charge carrier transport in these structures of finite lateral size. Yet unexplored oscillations in the frequency-dependent complex conductivity and a strong size dependence of the mobility are observed. The quantum nature of the charge carrier states results in oscillations in the frequency-dependent mobility for subresonant THz probing, seen in experiments. The effect is based on the lack of an energy continuum for the charge motion. In 2D systems the mobility is further governed by transitions in the two orthogonal x- and y-directions and depends nontrivially on the THz polarization, as well as the quantum well lateral aspect ratio, defining the energetic detuning of the lowest THz-photon transitions in both directions. We analyze the frequency, length, and effective mass dependencies.
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Affiliation(s)
- Michael T Quick
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Nina Owschimikow
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Alexander W Achtstein
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
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6
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Purschke DN, Pielmeier MRP, Üzer E, Ott C, Jensen C, Degg A, Vogel A, Amer N, Nilges T, Hegmann FA. Ultrafast Photoconductivity and Terahertz Vibrational Dynamics in Double-Helix SnIP Nanowires. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100978. [PMID: 34278600 DOI: 10.1002/adma.202100978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/30/2021] [Indexed: 06/13/2023]
Abstract
Tin iodide phosphide (SnIP), an inorganic double-helix material, is a quasi-1D van der Waals semiconductor that shows promise in photocatalysis and flexible electronics. However, the understanding of the fundamental photophysics and charge transport dynamics of this new material is limited. Here, time-resolved terahertz (THz) spectroscopy is used to probe the transient photoconductivity of SnIP nanowire films and measure the carrier mobility. With insight into the highly anisotropic electronic structure from quantum chemical calculations, an electron mobility as high as 280 cm2 V-1 s-1 along the double-helix axis and a hole mobility of 238 cm2 V-1 s-1 perpendicular to the double-helix axis are detected. Additionally, infrared-active (IR-active) THz vibrational modes are measured, which shows excellent agreement with first-principles calculations, and an ultrafast photoexcitation-induced charge redistribution is observed that reduces the amplitude of a twisting mode of the outer SnI helix on picosecond timescales. Finally, it is shown that the carrier lifetime and mobility are limited by a trap density greater than 1018 cm-3 . The results provide insight into the optical excitation and relaxation pathways of SnIP and demonstrate a remarkably high carrier mobility for such a soft and flexible material, suggesting that it could be ideally suited for flexible electronics applications.
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Affiliation(s)
- David N Purschke
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Markus R P Pielmeier
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Ebru Üzer
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Claudia Ott
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Charles Jensen
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Annabelle Degg
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Anna Vogel
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Naaman Amer
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Tom Nilges
- Department of Chemistry, Technical University of Munich, 85748, Garching bei München, Germany
| | - Frank A Hegmann
- Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
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7
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Xu J, Wang X, Nötzel R. Single-nanostructure bandgap engineering enabled by magnetic-pulling thermal evaporation growth. NANOSCALE ADVANCES 2020; 2:4305-4322. [PMID: 36132888 PMCID: PMC9417569 DOI: 10.1039/d0na00595a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/07/2020] [Indexed: 06/16/2023]
Abstract
Realizing the substantial potential of bottom-up 1D semiconductor nanostructures in developing functional nanodevices calls for dedicated single-nanostructure bandgap engineering by various growth approaches. Although thermal evaporation has been advised as a facile approach for most semiconductors to form 1D nanostructures from bottom-up, its capability of achieving single-nanostructure bandgap engineering was considered a challenge. In 2011, we succeeded in the direct growth of composition-graded CdS1-x Se x (0 ≤ x ≤ 1) nanowires by upgrading the thermal-evaporation tube furnace with a home-made magnetic-pulling module. This report aims to provide a comprehensive review of the latest advances in the single-nanostructure bandgap engineering enabled by the magnetic-pulling thermal evaporation growth. The report begins with the description of different magnetic-pulling thermal evaporation strategies associated with diverse examples of composition-engineered 1D nanostructures. Following is an elaboration on their optoelectronic applications based on the resulting single-nanostructure bandgap engineering, including monolithic white-light sources, proof-of-concept asymmetric light propagation and wavelength splitters, monolithic multi-color and white-light lasers, broadband-response photodetectors, high-performance transistors, and recently the most exciting single-nanowire spectrometer. In the end, this report concludes with some personal perspectives on the directions toward which future research might be advanced.
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Affiliation(s)
- Jinyou Xu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays, National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 People's Republic of China
| | - Xingyu Wang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays, National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 People's Republic of China
| | - Richard Nötzel
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays, National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 People's Republic of China
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Lu J, Liu H, Zhang X, Sow CH. One-dimensional nanostructures of II-VI ternary alloys: synthesis, optical properties, and applications. NANOSCALE 2018; 10:17456-17476. [PMID: 30211428 DOI: 10.1039/c8nr05019h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
One-dimensional (1D) nanostructures of II-VI ternary alloys are of prime interest due to their compatible features of both 1D nanostructures and semiconducting alloys. These features can facilitate materials with tunable bandgaps, which are crucial to the performance of photoelectrical devices. Herein, we present a comprehensive review summarizing the recent research progress pertinent to the diverse synthesis, optical fundamentals and applications of 1D nanostructures of II-VI ternary alloys. Considering multifunctional applications, the different growth mechanisms of the rational design and synthesis techniques are highlighted. Investigations of the fundamentals of the optical and photoelectrical properties of ternary alloyed II-VI semiconductors via the corresponding characterization techniques are also particularly discussed. Furthermore, we present the versatile potential practical applications of these materials. Finally, we extend the discussion to the most recent research advances on quaternary alloys, which provides a possible prospective forecast for the sustained development of alloyed 1D nanostructures.
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Affiliation(s)
- Junpeng Lu
- School of Physics, Southeast University, 2 Southeast University Road, Nanjing 211189, China.
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Lu J, Liu H, Sun J. Negative terahertz photoconductivity in 2D layered materials. NANOTECHNOLOGY 2017; 28:464001. [PMID: 28901296 DOI: 10.1088/1361-6528/aa8c28] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The remarkable qualities of 2D layered materials such as wide spectral coverage, high strength and great flexibility mean that ultrathin 2D layered materials have the potential to meet the criteria of next-generation optoelectronic devices. Photoconductivity is one of the critical parameters of materials applied to optoelectronics. In contrast to traditional semiconductors, specific ultrathin 2D layers present anomalous negative photoconductivity. This opens a new avenue for designing novel optoelectronic devices. It is important to have a deep understanding of the fundamentals of this anomalous response, in order to design and optimize such devices. In this review, we provide an overview of the observation of negative photoconductivity in 2D layered materials including graphene, topological insulators and transitional metal dichalcogenides. We also summarize recent reports on investigations into the fundamental mechanism using ultrafast terahertz (THz) spectroscopies. Finally, we conclude the review by discussing the existing challenges and proposing the possible prospects of this direction of research.
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Affiliation(s)
- Junpeng Lu
- School of Physics, Southeast University, Nanjing 211189, People's Republic of China
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