-
二维层状材料的能带漏斗效应为调控电荷转移提供了重要手段.然而，关于能带漏斗的实现及其对电荷转移速率的影响仍缺乏理解.本文通过解析推导和第一性原理计算方法，提出通过构建具有厚度梯度的MoS2实现能带漏斗效应，并分析能带漏斗效应对电荷转移速率的影响.结果表明，MoS2的带隙随层数减少呈单调递增趋势，使得双厚度梯度和三厚度梯度MoS2均可实现能带漏斗效应，电荷会从薄层区域往厚层区域定向传输.此外，不同层数MoS2界面处能级差诱导的驱动力是调控载流子聚集能力的重要因素，在双厚度梯度单层/块体MoS2的电荷转移速率可达4.97×1013s-1.这些结果为设计能带漏斗以及理解能带漏斗效应调控电荷转移行为提供物理基础.Energy funneling effect of two-dimensional materials provides an important method to modulate carrier transfer. However, the formation of energy funneling and its influences on the carrier transfer remain relatively uncharacterized. In this work, we investigate the energy funneling induced by the layer number gradient effect in MoS2 through atomic-bond-relaxation approach and first-principles calculations. We find that the bandgap of MoS2 monotonically increasing with decreasing the layer number, resulting in the conduction band minimum (valence band maximum) of thin layer MoS2 is being higher than (lower than) that of thick layer MoS2. Therefore, both dual thickness gradient and triple thickness gradient MoS2 can achieve the energy funneling effect. As a result, the carriers will be directionally transferred from the thin layer region to the thick layer region. According to Marcus theory, the carrier transfer rate is dependent on drive force induced by the energy level difference of different thicknesses of MoS2. For the dual thickness gradient MoS2, when the thickness difference between adjacent layers is the largest, the driving force is the highest, which is 1L/bulk. In addition, owing to the driving force of being smaller than the reorganization energy in dual thickness gradient MoS2, a large driving force corresponds to a high carrier transfer rate, resulting in a higher carrier transfer rate of 1L/bulk compared to other dual thickness gradient systems. For the triple thickness gradient MoS2, there are two consecutive interface energy differences that induce driving forces. However, the carrier transfer rate is exponentially correlated with the driving force. Therefore, the carrier transfer rate of dual thickness gradient MoS2 will be higher than that of the corresponding triple thickness gradient MoS2. Our results demonstrate that the energy funneling effect induced by thickness gradient can realize carrier accumulation in the thick layer region without the need for p-n junctions, which is of great benefit to the collection of photogenerated carrier. Future studies may leverage atomic force microscopy lithography and chemical vapor deposition to engineer thickness-gradient two-dimensional materials with enhanced optoelectronic properties.
-
Keywords:
- MoS2 /
- thickness gradient /
- energy funneling effect
-
[1] Jiang H, Zhang X K, Chen K L, He X Y, Liu Y H, Yu H H, Gao L, Hong M Y, Wang Y, Zhang Z, Zhang Y 2025 Nat. Mater. 24188
[2] Zhao J J, Liao M Z, Shen C, Wang Q Q, Yang R, Watanabe K, Taniguchi T, Huang Z H, Shi D X, Liu K H, Sun Z P, Feng J, Du L J, Zhang G Y 2025 Phys. Rev. Lett. 134086201
[3] Mak K F, Lee C, Hone J, Shan J, Heinz T F 2010 Phys. Rev. Lett. 105136805
[4] Li L K, Yu Y J, Ye G J, Ge Q Q, Ou X D, Wu H, Feng D L, Chen X H, Zhang Y B 2014 Nat. Nanotechnol. 9372
[5] Deng W, Wang L S, Liu J N, Yu X L, Chen F X 2021 Acta Phys. Sin. 70217302(in Chinese) [邓文，汪礼胜，刘嘉宁，余雪玲，陈凤翔2021 70217302]
[6] Yang F, Hu Y T, Ou J L, Li Q Y, Xie X X, Han H P, Cai C L, Ruan S C, Xiang B X 2025 ACS Photonics 122128
[7] Feng J, Qian X F, Huang C W and Li J 2012 Nat. Photonics 6866
[8] Li H, Contryman A W, Qian X F, Ardakani S M, Gong Y J, Wang X L, Weisse J M, Lee C H, Zhao J H, Ajayan P M, Li J, Manoharan H C, Zheng X L 2015 Nat. Commun. 67381
[9] Harats M G, Kirchhof J N, Qiao M X, Greben K, Bolotin K I 2020 Nat. Photonics 14324
[10] Lee J, Yun S J, Seo C, Cho K, Kim T S, An G H, Kang K, Lee H S and Kim J 2021 Nano Lett. 2143
[11] Liu J J, Zuo H L, Tan X, Dong J S 2024 Acta Phys. Sin. 73236801(in Chinese) [刘俊杰，左慧玲，谭鑫，董健生2024 73236801]
[12] Sun Z Y, Li Y, Xu B, Chen H, Wang P, Zhao S X, Li Yang, Gao B, Dou X M, Sun B Q, Zhen L, Xu C Y 2021 Adv. Optical Mater. 92100438
[13] Xu N, Pei X D, Qiu L P, Zhan L, Wang P, Shi Y, Li S L 2023 Adv. Mater. 352300618
[14] Ouyang G, Wang C X, Yang G W 2009 Chem. Rev. 1094221
[15] Zhu Z M, Zhang A, Ouyang G, Yang G W 2011 Appl. Phys. Lett. 98263112
[16] Dong J S, Zhao Y P, Ouyang G, Yang G W 2022 Appl. Phys. Lett. 120080501
[17] Sun C Q 2007 Prog. Solid State Chem. 351
[18] Jiang J W, Park H S, Rabczuk T 2013 J. Appl. Phys. 114064307
[19] Xiong S, Cao G X 2015 Nanotechnology 26185705
[20] Zhu Y F, Jiang Q 2016 Coordin. Chem. Rev. 3261
[21] Marcus R A 1956 J. Chem. Phys. 24966
[22] Zhang C, Lian L Y, Yang Z L, Zhang J B, Zhu H M 2019 J. Phys. Chem. Lett. 107665
[23] Kresse G, Hafner J. 1993 Phys. Rev. B 47558
[24] Blöchl P E 1994 Phys. Rev. B 5017953
[25] Kresse G 1996 Phys. Rev. B 5411169
[26] Yun W S, Han S W, Hong S C, Kim I G, Lee J D 2012 Phys. Rev. B 85033305
[27] Li T S 2012 Phys. Rev. B 85235407
[28] Kang J, Tongay S, Zhou J, Li J B, Wu J Q 2013 Appl. Phys. Lett. 102012111
[29] Dong J S, Liu J J, Liao W H, Yang X X, He Y, Ouyang G 2024 J. Appl. Phys. 136125302
[30] Chu T, Ilatikhameneh H, Klimeck G, Rahman R, Chen Z H 2015 Nano Lett. 158000
[31] Lee H S, Min S W, Chang Y G, Park M K, Nam T, Kim H, Kim J H, Ryu S, Im S 2012 Nano Lett. 123695
[32] Wang J H, Ding T, Gao K M, Wang L F, Zhou P W, Wu K F 2021 Nat. Commun. 126333
[33] Furchi M M, Pospischil A, Libisch F, Burgdörfer J, Mueller T 2014 Nano Lett. 144785
[34] Lee C H, Lee G H, Zande A M, Chen W C, Li Y L, Han M Y, Cui X, Arefe G, Nuckolls C, Heinz T F, Guo J, Hone J, Kim P 2014 Nat. Nanotechnol. 9676
[35] Cao G Y, Shang A X, Zhang C, Gong Y P, Li S J, Bao Q L, Li X F 2016 Nano Energy 30260
计量
- 文章访问数: 44
- PDF下载量: 1
- 被引次数: 0
下载:
