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Song S, Kim SH, Han KH, Kim HJ, Yu HY. In-Depth Analysis on Self Alignment Effect of the Fermi-Level Using Graphene on Both n- and p-Type Semiconductors. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 38033204 DOI: 10.1021/acsami.3c14386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Optimizing the contact structure while reducing the contact resistance in advanced transistors has become an extremely challenging problem. Because the existing techniques are limited to controlling only one semiconductor type, either n- or p-type, owing to their work function differences, significant challenges are encountered in the integration of a contact structure and metal suitable for both n- and p-type semiconductors. This is a formidable drawback of the complementary metal-oxide-semiconductor (CMOS) technology. In this paper, we demonstrate the effectiveness of a metal/graphene/semiconductor (MGrS) as a universal source/drain contact structure for both n- and p-type transistors. The MGrS contact structure significantly enhanced the reverse current density (JR) and reduced the Schottky barrier height (SBH) for both semiconductor types. From the analysis of the SBH values and their relationship with the metal work function, which refers to the S-parameter, the van der Waals contact of graphene (Gr) effectively alleviated the Fermi level (FL) pinning for both semiconductor types, reducing the metal-induced gap states (MIGS) at the Gr/semiconductor interface. Furthermore, Gr effectively modulated the work function of the contact metal to yield a position favorable for each semiconductor type. Consequently, a single MGrS contact structure on a Si substrate resulted in excellent Ohmic contacts in both n- and p-type Si, with SBH values reduced to 0.012 and 0.024 eV for n- and p-type Si, respectively. This new approach for integrating the contact structures of semiconductor types will lead to extended capabilities for high-performance device applications and CMOS logical circuitry.
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Affiliation(s)
- Sungjoo Song
- Department of Semiconductor Systems Engineering, Korea University, Seoul 02841, Korea
| | - Seung-Hwan Kim
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Kyu-Hyun Han
- Department of Electrical Engineering, Korea University, Seoul 02841, Korea
| | - Hyung-Jun Kim
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
- Division of Nano & Information Technology, KIST School, Korea University of Science & Technology (UST), Seoul 02792, Republic of Korea
| | - Hyun-Yong Yu
- Department of Semiconductor Systems Engineering, Korea University, Seoul 02841, Korea
- Department of Electrical Engineering, Korea University, Seoul 02841, Korea
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Hu X, Jiang H, Lu LX, Zhao SX, Li Y, Zhen L, Xu CY. Revisiting the Hetero-Interface of Electrolyte/2D Materials in an Electric Double Layer Device. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2301798. [PMID: 37357158 DOI: 10.1002/smll.202301798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/08/2023] [Indexed: 06/27/2023]
Abstract
Electric double layer (EDL) devices based on 2D materials have made great achievements for versatile electronic and opto-electronic applications; however, the ion dynamics and electric field distribution of the EDL at the electrolyte/2D material interface and their influence on the physical properties of 2D materials have not been clearly clarified. In this work, by using Kelvin probe force microscope and steady/transient optical techniques, the character of the EDL and its influence on the optical properties of monolayer transition metal dichalcogenides (TMDs) are probed. The potential drop, unscreened EDL potential distribution, and accumulated carriers at the electrolyte/TMD interface are revealed, which can be explained by nonlinear Thomas-Fermi theory. By monitoring the potential distribution along the channel, the evolution of the electric field-induced lateral junction in the TMD EDL transistor is accessed, giving rise to the better exploration of EDL device physics. More importantly, EDL gate-dependent carrier recombination and exciton-exciton annihilation in monolayer TMDs on lithium-ion solid state electrolyte (Li2 Al2 SiP2 TiO13 ) are evaluated for the first time, benefiting from the understanding of the interaction between ions, carriers, and excitons. The work will deepen the understanding of the EDL for the exploitation of functional device applications.
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Affiliation(s)
- Xin Hu
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
- MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China
| | - Hao Jiang
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Liang-Xing Lu
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Shou-Xin Zhao
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
- MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China
| | - Yang Li
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
- MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China
| | - Liang Zhen
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
- MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China
- Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Cheng-Yan Xu
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
- MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China
- Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
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Chou WY, Peng SK, Chang FH, Cheng HL, Ruan JJ, Ho TY. Ferromagnetism above Room Temperature in a Ni-Doped Organic-Based Magnetic Semiconductor. ACS APPLIED MATERIALS & INTERFACES 2021; 13:34962-34972. [PMID: 34269055 DOI: 10.1021/acsami.1c08967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Ferromagnetic semiconductors with structural flexibility are an indispensable feature for future flexible spin-electronic applications. In this case, we introduce magnetic ingredients into an organic semiconductor, namely, pentacene, to form a ferromagnetic organic semiconductor (FOS). The first observation for ferromagnetic Ni-doped pentacene semiconductors at room temperature in the field of semiconductor spintronics is reported in this article. To date, the mechanism of FOSs with ferromagnetism is not understood yet, especially when their Curie temperature is enhanced above room temperature. Here, we demonstrate dopants of Ni atoms and the modulation of the growth temperature in the FOS films to achieve room-temperature ferromagnetic properties in a series of FOS films, one of which has a maximum coercivity of 257.6 Oe. The spin-exchange interaction between a Ni atom and a pentacene molecule is detected through the magnetic hysteresis obtained using a superconducting quantum interference device magnetometer. We verify the effectiveness of this spin coupling through magnetic force microscopy, Raman spectroscopy, scanning Kelvin probe microscopy, and theoretical simulation. A model for the indirect spin coupling between Ni atoms is proposed for the mechanism of room-temperature ferromagnetic ordering of spins due to the exchange force indirectly. We believe that the π-electrons of pentacene molecules at the triple state for this model can support the spin coupling of electrons of Ni atoms. Our findings facilitate the development of brand-new spintronic devices with structural flexibility and room-temperature ferromagnetism.
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Affiliation(s)
- Wei-Yang Chou
- Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan
| | - Sheng-Kuang Peng
- Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan
| | - Fu-Hsuan Chang
- Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan
| | - Horng-Long Cheng
- Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan
| | - Jr-Jeng Ruan
- Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Tsung-Yeh Ho
- Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan
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Zhang L, Zhang XW, Li ZA, Chen DH, Wang ZQ, Pang SM, Zhou L, Wu DG, Ke LS, Nan CB. Distribution model of lowly volatile impurity in rare earth metal purified by vacuum distillation. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Electronic and Transport Properties of Epitaxial Graphene on SiC and 3C-SiC/Si: A Review. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10124350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The electronic and transport properties of epitaxial graphene are dominated by the interactions the material makes with its surroundings. Based on the transport properties of epitaxial graphene on SiC and 3C-SiC/Si substrates reported in the literature, we emphasize that the graphene interfaces formed between the active material and its environment are of paramount importance, and how interface modifications enable the fine-tuning of the transport properties of graphene. This review provides a renewed attention on the understanding and engineering of epitaxial graphene interfaces for integrated electronics and photonics applications.
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