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Mičky S, Bodík M, Mičetić M, Fetzer F, Strienz M, Held V, Jergel M, Schnepf A, Schreiber F, Šiffalovič P. Multilayer Langmuir Film of Monodisperse Au Nanoclusters: Unusual Growth via Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14850-14856. [PMID: 36440917 DOI: 10.1021/acs.langmuir.2c02514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The assembly of nanomaterials into thin films is an important area in the nanofabrication of novel devices. The monodispersity of nanoparticles plays an essential role in the resulting quality of the assembled mono- and multilayers. Larger polydispersity leads to smaller lateral correlation lengths and smaller domains of aligned nanoparticles, thus resulting in more point and line defects. Perfectly monodisperse nanoparticles should therefore minimize the number of defects in the assembled films. Despite tremendous progress in reducing the polydispersity of nanoparticles, there has been limited research on the assembly of thin films out of perfectly monodisperse nanoclusters. Here, we show a formation of Langmuir films using perfectly monodisperse gold nanoclusters with composition Au32(nBu3P)12Cl8 exhibiting a diameter of 1.8 nm. Using both in situ and ex situ small-angle X-ray scattering, we show that the monolayer formed on a Langmuir-Blodgett trough exhibits long-range order. Moreover, after compressing the monolayer, we found that the stress accumulated prior to the monolayer collapse triggers a transition to a short-range order not previously reported. If such monolayer is compressed further, the second layer is not formed as in the case of standard nanoparticles. Instead, a growth of islands by an odd number of layers is observed, leading to a thin film with a structure consisting of two different orientations of the hexagonal lattice. Such anomalous behavior may have implications for the possibilities of thin-film formation.
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Affiliation(s)
- Simon Mičky
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11Bratislava, Slovakia
| | - Michal Bodík
- Nanotechnology Group, ETH Zürich, Säumerstrasse 4, 8803Rüschlikon, Switzerland
| | | | - Florian Fetzer
- Chemistry Department, University Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
| | - Markus Strienz
- Chemistry Department, University Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
| | - Vladimír Held
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11Bratislava, Slovakia
| | - Matej Jergel
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11Bratislava, Slovakia
- Center for Advanced Materials Application, Dúbravská cesta 9, 845 11Bratislava, Slovakia
| | - Andreas Schnepf
- Chemistry Department, University Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, D-72076Tübingen, Germany
| | - Peter Šiffalovič
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11Bratislava, Slovakia
- Center for Advanced Materials Application, Dúbravská cesta 9, 845 11Bratislava, Slovakia
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Wang C, Li Y, Jin Y, Guo G, Song Y, Huang H, He H, Wang A. One-Step Synergistic Treatment Approach for High Performance Amorphous InGaZnO Thin-Film Transistors Fabricated at Room Temperature. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3481. [PMID: 36234608 PMCID: PMC9565279 DOI: 10.3390/nano12193481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Amorphous InGaZnO (a-InGaZnO) is currently the most prominent oxide semiconductor complement to low-temperature polysilicon for thin-film transistor (TFT) applications in next-generation displays. However, balancing the transmission performance and low-temperature deposition is the primary obstacle in the application of a-InGaZnO TFTs in the field of ultra-high resolution optoelectronic display. Here, we report that a-InGaZnO:O TFT prepared at room temperature has high transport performance, manipulating oxygen vacancy (VO) defects through an oxygen-doped a-InGaZnO framework. The main electrical properties of a-InGaZnO:O TFTs included high field-effect mobility (µFE) of 28 cm2/V s, a threshold voltage (Vth) of 0.9 V, a subthreshold swing (SS) of 0.9 V/dec, and a current switching ratio (Ion/Ioff) of 107; significant improvements over a-InGaZnO TFTs without oxygen plasma. A possible reason for this is that appropriate oxygen plasma treatment and room temperature preparation technology jointly play a role in improving the electrical performance of a-InGaZnO TFTs, which could not only increase carrier concentration, but also reduce the channel-layer surface defects and interface trap density of a-InGaZnO TFTs. These provides a powerful way to synergistically boost the transport performance of oxide TFTs fabricated at room temperature.
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Affiliation(s)
- Chunlan Wang
- School of Science, Xi’an Polytechnic University, Xi’an 710048, China
| | - Yuqing Li
- School of Science, Xi’an Polytechnic University, Xi’an 710048, China
| | - Yebo Jin
- School of Science, Xi’an Polytechnic University, Xi’an 710048, China
| | - Gangying Guo
- School of Science, Xi’an Polytechnic University, Xi’an 710048, China
| | - Yongle Song
- School of Science, Xi’an Polytechnic University, Xi’an 710048, China
| | - Hao Huang
- Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Material, School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Han He
- Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Material, School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Aolin Wang
- Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Material, School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
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Lai H, Zhou Y, Zhou H, Zhang N, Ding X, Liu P, Wang X, Xie W. Photoinduced Multi-Bit Nonvolatile Memory Based on a van der Waals Heterostructure with a 2D-Perovskite Floating Gate. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2110278. [PMID: 35289451 DOI: 10.1002/adma.202110278] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/17/2022] [Indexed: 06/14/2023]
Abstract
The development of floating-gate nonvolatile memory (FGNVM) is limited by the charge storage, retention and transfer ability of the charge-trapping layer. Here, it is demonstrated that due to the unique alternate inorganic/organic chain structure and superior optical sensitivity, an insulating 2D Ruddlesden-Popper perovskite (2D-RPP) layer can function both as an excellent charge-storage layer and a photosensitive layer. Optoelectronic memory composed of a MoS2 /hBN/2D-RPP (MBR) van der Waals heterostructure is demonstrated. The MBR device exhibits unique light-controlled charge-storage characteristics, with maximum memory window up to 92 V, high on/off ratio of 104 , negligible degeneration over 103 s, >1000 program/erase cycles, and write speed of 500 µs. Dependent on the initial states, the MBR optoelectronic memory can be programmed in both positive photoconductivity (PPC) and negative photoconductivity (NPC) modes, with up to 11 and 22 distinct resistance states, respectively. The optical program power for each bit is as low as 36/10 pJ for PPC/NPC. The results not only reveal the potential of 2D-RPP as a superior charge-storage medium in floating-gate memory, but also provides an effective strategy toward fast, low-power and stable optical multi-bit storage and neuromorphic computing.
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Affiliation(s)
- Haojie Lai
- Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Yang Zhou
- Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Huabin Zhou
- Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Ning Zhang
- Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Xidong Ding
- School of Physics, Sun Yat-sen University, Guangzhou, Guangdong, 510275, China
| | - Pengyi Liu
- Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong, 510632, China
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Xiaomu Wang
- School of Electronic Science and Technology, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Weiguang Xie
- Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, Guangdong, 510632, China
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou, Guangdong, 510632, China
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Oxygen Concentration Effect on Conductive Bridge Random Access Memory of InWZnO Thin Film. NANOMATERIALS 2021; 11:nano11092204. [PMID: 34578520 PMCID: PMC8466751 DOI: 10.3390/nano11092204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/22/2021] [Accepted: 08/25/2021] [Indexed: 01/10/2023]
Abstract
In this study, the influence of oxygen concentration in InWZnO (IWZO), which was used as the switching layer of conductive bridge random access memory, (CBRAM) is investigated. With different oxygen flow during the sputtering process, the IWZO film can be fabricated with different oxygen concentrations and different oxygen vacancy distribution. In addition, the electrical characteristics of CBRAM device with different oxygen concentration are compared and further analyzed with an atomic force microscope and X-ray photoelectron spectrum. Furthermore, a stacking structure with different bilayer switching is also systematically discussed. Compared with an interchange stacking layer and other single layer memory, the CBRAM with specific stacking sequence of bilayer oxygen-poor/-rich IWZO (IWZOx/IWZOy, x < y) exhibits more stable distribution of a resistance state and also better endurance (more than 3 × 104 cycles). Meanwhile, the memory window of IWZOx/IWZOy can even be maintained over 104 s at 85 °C. Those improvements can be attributed to the oxygen vacancy distribution in switching layers, which may create a suitable environment for the conductive filament formation or rupture. Therefore, it is believed that the specific stacking bilayer IWZO CBRAM might further pave the way for emerging memory applications.
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