Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full Encapsulation
The field-effect control of the electrical and optical properties of two-dimensional (2D) van der Waals semiconductors (vdW) is one important aspect of this novel class of materials. Thanks to their reduced thickness and decreased screening, electric fields can easily penetrate in a 2D semiconductor...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/24/4425 |
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| author | Anna Di Renzo Onur Çakıroğlu Felix Carrascoso Hao Li Giuseppe Gigli Kenji Watanabe Takashi Taniguchi Carmen Munuera Aurora Rizzo Andres Castellanos-Gomez Rosanna Mastria Riccardo Frisenda |
| author_facet | Anna Di Renzo Onur Çakıroğlu Felix Carrascoso Hao Li Giuseppe Gigli Kenji Watanabe Takashi Taniguchi Carmen Munuera Aurora Rizzo Andres Castellanos-Gomez Rosanna Mastria Riccardo Frisenda |
| author_sort | Anna Di Renzo |
| collection | DOAJ |
| description | The field-effect control of the electrical and optical properties of two-dimensional (2D) van der Waals semiconductors (vdW) is one important aspect of this novel class of materials. Thanks to their reduced thickness and decreased screening, electric fields can easily penetrate in a 2D semiconductor and thus modulate their charge density and their properties. In literature, the field effect is routinely used to fabricate atomically thin field-effect transistors based on 2D semiconductors. Apart from the tuning of the electrical transport, it has been demonstrated that the field effect can also be used to modulate the excitonic optical emission of 2D transition metal dichalcogenides such as MoS<sub>2</sub> or WSe<sub>2</sub>. In this paper, we present some recent experiments on the field-effect control of the optical and excitonic properties of the monolayer WS<sub>2</sub>. Using the deterministic transfer of van der Waals materials, we fabricate planar single-layer WS<sub>2</sub> devices contacted by a gold electrode and partially sandwiched between two insulating hexagonal boron nitride (hBN) flakes. Thanks to the planar nature of the device, we can optically access both the hBN encapsulated and the unencapsulated WS<sub>2</sub> regions and compare the field-effect control of the exciton population in the two cases. We find that the encapsulation strongly increases the range of tunability of the optical emission of WS<sub>2</sub>, allowing us to tune the photoluminescence emission from excitons-dominated to trions-dominated. We also discuss how the full encapsulation of WS<sub>2</sub> with hBN helps reduce spurious hysteretic effects in the field-effect control of the optical properties, similar to what has been reported for 2D vdW field-effect transistors. |
| first_indexed | 2024-03-09T16:01:38Z |
| format | Article |
| id | doaj.art-c1a39677a96048ffbcb5b2abc02a6377 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T16:01:38Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-c1a39677a96048ffbcb5b2abc02a63772023-11-24T17:04:09ZengMDPI AGNanomaterials2079-49912022-12-011224442510.3390/nano12244425Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full EncapsulationAnna Di Renzo0Onur Çakıroğlu1Felix Carrascoso2Hao Li3Giuseppe Gigli4Kenji Watanabe5Takashi Taniguchi6Carmen Munuera7Aurora Rizzo8Andres Castellanos-Gomez9Rosanna Mastria10Riccardo Frisenda11Department of Mathematics and Physics “Ennio De Giorgi”, University of Salento, Via Arnesano, 73100 Lecce, ItalyMaterials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, SpainMaterials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, SpainMaterials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, SpainDepartment of Mathematics and Physics “Ennio De Giorgi”, University of Salento, Via Arnesano, 73100 Lecce, ItalyResearch Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, JapanInternational Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, JapanMaterials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, SpainNational Research Council, Institute of Nanotechnology (CNR-NANOTEC), Via Monteroni, 73100 Lecce, ItalyMaterials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, SpainNational Research Council, Institute of Nanotechnology (CNR-NANOTEC), Via Monteroni, 73100 Lecce, ItalyMaterials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, SpainThe field-effect control of the electrical and optical properties of two-dimensional (2D) van der Waals semiconductors (vdW) is one important aspect of this novel class of materials. Thanks to their reduced thickness and decreased screening, electric fields can easily penetrate in a 2D semiconductor and thus modulate their charge density and their properties. In literature, the field effect is routinely used to fabricate atomically thin field-effect transistors based on 2D semiconductors. Apart from the tuning of the electrical transport, it has been demonstrated that the field effect can also be used to modulate the excitonic optical emission of 2D transition metal dichalcogenides such as MoS<sub>2</sub> or WSe<sub>2</sub>. In this paper, we present some recent experiments on the field-effect control of the optical and excitonic properties of the monolayer WS<sub>2</sub>. Using the deterministic transfer of van der Waals materials, we fabricate planar single-layer WS<sub>2</sub> devices contacted by a gold electrode and partially sandwiched between two insulating hexagonal boron nitride (hBN) flakes. Thanks to the planar nature of the device, we can optically access both the hBN encapsulated and the unencapsulated WS<sub>2</sub> regions and compare the field-effect control of the exciton population in the two cases. We find that the encapsulation strongly increases the range of tunability of the optical emission of WS<sub>2</sub>, allowing us to tune the photoluminescence emission from excitons-dominated to trions-dominated. We also discuss how the full encapsulation of WS<sub>2</sub> with hBN helps reduce spurious hysteretic effects in the field-effect control of the optical properties, similar to what has been reported for 2D vdW field-effect transistors.https://www.mdpi.com/2079-4991/12/24/4425van der Waals materialsWS<sub>2</sub>hBNphotoluminescenceexcitons |
| spellingShingle | Anna Di Renzo Onur Çakıroğlu Felix Carrascoso Hao Li Giuseppe Gigli Kenji Watanabe Takashi Taniguchi Carmen Munuera Aurora Rizzo Andres Castellanos-Gomez Rosanna Mastria Riccardo Frisenda Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full Encapsulation Nanomaterials van der Waals materials WS<sub>2</sub> hBN photoluminescence excitons |
| title | Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full Encapsulation |
| title_full | Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full Encapsulation |
| title_fullStr | Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full Encapsulation |
| title_full_unstemmed | Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full Encapsulation |
| title_short | Enhanced Field-Effect Control of Single-Layer WS<sub>2</sub> Optical Features by hBN Full Encapsulation |
| title_sort | enhanced field effect control of single layer ws sub 2 sub optical features by hbn full encapsulation |
| topic | van der Waals materials WS<sub>2</sub> hBN photoluminescence excitons |
| url | https://www.mdpi.com/2079-4991/12/24/4425 |
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