Accelerated carrier recombination by grain boundary/edge defects in MBE grown transition metal dichalcogenides
Defect-carrier interaction in transition metal dichalcogenides (TMDs) plays important roles in carrier relaxation dynamics and carrier transport, which determines the performance of electronic devices. With femtosecond laser time-resolved spectroscopy, we investigated t...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2018-05-01
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| Series: | APL Materials |
| Online Access: | http://dx.doi.org/10.1063/1.5022339 |
| _version_ | 1819039069222469632 |
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| author | Ke Chen Anupam Roy Amritesh Rai Hema C. P. Movva Xianghai Meng Feng He Sanjay K. Banerjee Yaguo Wang |
| author_facet | Ke Chen Anupam Roy Amritesh Rai Hema C. P. Movva Xianghai Meng Feng He Sanjay K. Banerjee Yaguo Wang |
| author_sort | Ke Chen |
| collection | DOAJ |
| description | Defect-carrier interaction in transition metal dichalcogenides (TMDs) plays important
roles in carrier relaxation dynamics and carrier transport, which determines the
performance of electronic devices. With femtosecond laser time-resolved spectroscopy, we
investigated the effect of grain boundary/edge defects on the ultrafast dynamics of
photoexcited carrier in molecular beam epitaxy (MBE)-grown MoTe2 and
MoSe2. We found that, comparing with exfoliated samples, the carrier
recombination rate in MBE-grown samples accelerates by about 50 times. We attribute this
striking difference to the existence of abundant grain boundary/edge defects in MBE-grown
samples, which can serve as effective recombination centers for the photoexcited carriers.
We also observed coherent acoustic phonons in both exfoliated and MBE-grown
MoTe2, indicating strong electron-phonon coupling in this materials. Our
measured sound velocity agrees well with the previously reported result of theoretical
calculation. Our findings provide a useful reference for the fundamental parameters:
carrier lifetime and sound velocity and reveal the undiscovered carrier recombination
effect of grain boundary/edge defects, both of which will facilitate the defect
engineering in TMD materials for high speed opto-electronics. |
| first_indexed | 2024-12-21T08:47:20Z |
| format | Article |
| id | doaj.art-4e2980ed91d34ab6a1b2458bd009df0c |
| institution | Directory Open Access Journal |
| issn | 2166-532X |
| language | English |
| last_indexed | 2024-12-21T08:47:20Z |
| publishDate | 2018-05-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | APL Materials |
| spelling | doaj.art-4e2980ed91d34ab6a1b2458bd009df0c2022-12-21T19:09:48ZengAIP Publishing LLCAPL Materials2166-532X2018-05-0165056103056103-710.1063/1.5022339004805APMAccelerated carrier recombination by grain boundary/edge defects in MBE grown transition metal dichalcogenidesKe Chen0Anupam Roy1Amritesh Rai2Hema C. P. Movva3Xianghai Meng4Feng He5Sanjay K. Banerjee6Yaguo Wang7Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USAMicroelectronics Research Center and Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USAMicroelectronics Research Center and Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USAMicroelectronics Research Center and Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USADepartment of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USADepartment of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USAMicroelectronics Research Center and Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USADepartment of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USADefect-carrier interaction in transition metal dichalcogenides (TMDs) plays important roles in carrier relaxation dynamics and carrier transport, which determines the performance of electronic devices. With femtosecond laser time-resolved spectroscopy, we investigated the effect of grain boundary/edge defects on the ultrafast dynamics of photoexcited carrier in molecular beam epitaxy (MBE)-grown MoTe2 and MoSe2. We found that, comparing with exfoliated samples, the carrier recombination rate in MBE-grown samples accelerates by about 50 times. We attribute this striking difference to the existence of abundant grain boundary/edge defects in MBE-grown samples, which can serve as effective recombination centers for the photoexcited carriers. We also observed coherent acoustic phonons in both exfoliated and MBE-grown MoTe2, indicating strong electron-phonon coupling in this materials. Our measured sound velocity agrees well with the previously reported result of theoretical calculation. Our findings provide a useful reference for the fundamental parameters: carrier lifetime and sound velocity and reveal the undiscovered carrier recombination effect of grain boundary/edge defects, both of which will facilitate the defect engineering in TMD materials for high speed opto-electronics.http://dx.doi.org/10.1063/1.5022339 |
| spellingShingle | Ke Chen Anupam Roy Amritesh Rai Hema C. P. Movva Xianghai Meng Feng He Sanjay K. Banerjee Yaguo Wang Accelerated carrier recombination by grain boundary/edge defects in MBE grown transition metal dichalcogenides APL Materials |
| title | Accelerated carrier recombination by grain boundary/edge defects in MBE grown
transition metal dichalcogenides |
| title_full | Accelerated carrier recombination by grain boundary/edge defects in MBE grown
transition metal dichalcogenides |
| title_fullStr | Accelerated carrier recombination by grain boundary/edge defects in MBE grown
transition metal dichalcogenides |
| title_full_unstemmed | Accelerated carrier recombination by grain boundary/edge defects in MBE grown
transition metal dichalcogenides |
| title_short | Accelerated carrier recombination by grain boundary/edge defects in MBE grown
transition metal dichalcogenides |
| title_sort | accelerated carrier recombination by grain boundary edge defects in mbe grown transition metal dichalcogenides |
| url | http://dx.doi.org/10.1063/1.5022339 |
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