Single-material MoS2 thermoelectric junction enabled by substrate engineering
Source abstract
Abstract
Abstract To realize a thermoelectric power generator, typically, a junction between two materials with different Seebeck coefficients needs to be fabricated. Such differences in Seebeck coefficients can be induced by doping, which renders it difficult when working with two-dimensional (2d) materials. However, doping is not the only way to modulate the Seebeck coefficient of a 2d material. Substrate-altered electron–phonon scattering mechanisms can also be used to this end. Here, we employ the substrate effects to form a thermoelectric junction in ultrathin, few-layer MoS2 films. We investigated the junctions with a combination of scanning photocurrent microscopy and scanning thermal microscopy. This allows us to reveal that thermoelectric junctions form across the substrate-engineered parts. We attribute this to a gating effect induced by interfacial charges in combination with alterations in the electron–phonon scattering mechanisms. This work demonstrates that substrate engineering is a promising strategy for developing future compact thin-film thermoelectric power generators.
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Research context
OpenAlex topics: 2D Materials and Applications · Advanced Thermoelectric Materials and Devices · Quantum Dots Synthesis And Properties
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (57)
Show source-provided references
1. Chen, J. H. et al. Charged-impurity scattering in graphene. Nat. Phys. 4, 377–381 (2008).10.1038/nphys935 ↗
2. Zhang, Y., Brar, V. W., Girit, C., Zettl, A. & Crommie, M. F. Origin of spatial charge inhomogeneity in graphene. Nat. Phys. 5, 722–726 (2009).10.1038/nphys1365 ↗
3. Wang, Q. H. et al. Understanding and controlling the substrate effect on graphene electron-transfer chemistry via reactivity imprint lithography. Nat. Chem. 4, 724–732 (2012).10.1038/nchem.1421 ↗
4. Bao, W., Cai, X., Kim, D., Sridhara, K. & Fuhrer, M. S. High mobility ambipolar MoS2 field-effect transistors: Substrate and dielectric effects. Appl. Phys. Lett. 102, 042104 (2013).10.1063/1.4789365 ↗
5. Robinson, B. J. et al. Structural, optical and electrostatic properties of single and few-layers MoS2: effect of substrate. 2D Mater. 2, 015005 (2015).10.1088/2053-1583/2/1/015005 ↗
6. Wang, L., Nilsson, Z. N., Tahir, M., Chen, H. & Sambur, J. B. Influence of the substrate on the optical and photo-electrochemical properties of monolayer MoS2. ACS Appl. Mater. Interfaces 12, 15034–15042 (2020).10.1021/acsami.9b21230 ↗
7. Buscema, M., Steele, G. A., van der Zant, H. S. J. & Castellanos-Gomez, A. The effect of the substrate on the Raman and photoluminescence emission of single-layer MoS2. Nano Res. 7, 561–571 (2014).10.1007/s12274-014-0424-0 ↗
8. Sercombe, D. et al. Optical investigation of the natural electron doping in thin MoS2 films deposited on dielectric substrates. Sci. Rep. 3, 1–6 (2013).10.1038/srep03489 ↗
9. Wu, J. et al. Large enhancement of thermoelectric performance in MoS2/h-BN heterostructure due to vacancy-induced band hybridization. Proc. Natl Acad. Sci. USA 117, 13929–13936 (2020).10.1073/pnas.2007495117 ↗
10. Herring, C. Theory of the thermoelectric power of semiconductors. Phys. Rev. 96, 1163–1187 (1954).10.1103/PhysRev.96.1163 ↗
11. Ng, H. K., Chi, D. & Hippalgaonkar, K. Effect of dimensionality on thermoelectric powerfactor of molybdenum disulfide. J. Appl. Phys. 121, 204303 (2017).10.1063/1.4984138 ↗
12. Cui, X. et al. Multi-terminal transport measurements of MoS2 using a van der Waals heterostructure device platform. Nat. Nanotechnol. 10, 534–540 (2015).10.1038/nnano.2015.70 ↗
13. Jiang, J. et al. Flexo-photovoltaic effect in MoS2. Nat. Nanotechnol. 16, 894–901 (2021).10.1038/s41565-021-00919-y ↗
14. Rice, C. et al. Raman-scattering measurements and first-principles calculations of strain-induced phonon shifts in monolayer MoS2. Phys. Rev. B Condens. Matter Mater. Phys. 87, 081307 (2013).10.1103/PhysRevB.87.081307 ↗
15. Hippalgaonkar, K. et al. High thermoelectric power factor in two-dimensional crystals of MoS2. Phys. Rev. B 95, 115407 (2017).10.1103/PhysRevB.95.115407 ↗
16. Kayyalha, M., Maassen, J., Lundstrom, M., Shi, L. & Chen, Y. P. Gate-tunable and thickness-dependent electronic and thermoelectric transport in few-layer MoS2. J. Appl. Phys. 120, 134305 (2016).10.1063/1.4963364 ↗
17. Liu, L., Lu, Y. & Guo, J. On monolayer MoS2 field-effect transistors at the scaling limit. IEEE Trans. Electron Devices 60, 4133–4139 (2013).10.1109/TED.2013.2284591 ↗
18. Dagan, R. et al. Two-dimensional charge carrier distribution in MoS2 monolayer and multilayers. Appl. Phys. Lett. 114, 101602 (2019).10.1063/1.5078711 ↗
19. Chae, W. H., Cain, J. D., Hanson, E. D., Murthy, A. A. & Dravid, V. P. Substrate-induced strain and charge doping in CVD-grown monolayer MoS2. Appl. Phys. Lett. 111, 143106 (2017).10.1063/1.4998284 ↗
20. Castellanos-Gomez, A. et al. Deterministic transfer of two-dimensional materials by all-dry viscoelastic stamping. 2D Mater. 1, 011002 (2014).10.1088/2053-1583/1/1/011002 ↗
21. Mehmood, N., Rasouli, H. R., Çakıroğlu, O. & Kasırga, T. S. Photocurrent generation in a metallic transition-metal dichalcogenide. Phys. Rev. B 97, 195412 (2018).10.1103/PhysRevB.97.195412 ↗
22. Rasouli, H. R. et al. Electric-field-induced reversible phase transitions in a spontaneously ion-intercalated 2D metal oxide. Nano Lett. 21, 3997–4005 (2021).10.1021/acs.nanolett.1c00735 ↗
23. Razeghi, M., Üstünçelik, M., Shabani, F., Demir, H. V. & Kasırga, T. S. Plasmon-enhanced photoresponse of single silver nanowires and their network devices. Nanoscale Horiz. 7, 396–402 (2022).10.1039/D1NH00629K ↗
24. Kim, B.-K. et al. Origins of genuine Ohmic van der Waals contact between indium and MoS2. npj 2D Mater. Appl. 5, 9 (2021).10.1038/s41699-020-00191-z ↗
25. Wang, Y. et al. Van der Waals contacts between three-dimensional metals and two-dimensional semiconductors. Nature 568, 70–74 (2019).10.1038/s41586-019-1052-3 ↗
26. Kasirga, T. S. Thermal Conductivity Measurements in Atomically Thin Materials and Devices (Springer Singapore, 2020).10.1007/978-981-15-5348-6 ↗
27. Kasirga, T. S. et al. Photoresponse of a strongly correlated material determined by scanning photocurrent microscopy. Nat. Nanotechnol 7, 723–727 (2012).10.1038/nnano.2012.176 ↗
28. Çakıroğlu, O. et al. Thermal conductivity measurements in nanosheets via bolometric effect. 2D Mater. 7, 035003 (2020).10.1088/2053-1583/ab8048 ↗
29. Buscema, M. et al. Large and tunable photothermoelectric effect in single-layer MoS2. Nano Lett. 13, 358–363 (2013).10.1021/nl303321g ↗
30. Zhang, Y. et al. Photothermoelectric and photovoltaic effects both present in MoS2. Sci. Rep. 5, 1–7 (2015).
31. Utama, M. I. B. et al. A dielectric-defined lateral heterojunction in a monolayer semiconductor. Nat. Electron. 2, 60–65 (2019).10.1038/s41928-019-0207-4 ↗
32. Harzheim, A., Evangeli, C., Kolosov, O. V. & Gehring, P. Direct mapping of local Seebeck coefficient in 2D material nanostructures via scanning thermal gate microscopy. 2D Mater. 7, 041004 (2020).10.1088/2053-1583/aba333 ↗
33. Spièce, J. et al. Quantifying thermal transport in buried semiconductor nanostructures: via cross-sectional scanning thermal microscopy. Nanoscale 13, 10829–10836 (2021).10.1039/D0NR08768H ↗
34. Spiece, J. et al. Improving accuracy of nanothermal measurements via spatially distributed scanning thermal microscope probes. J. Appl. Phys. 124, 015101 (2018).10.1063/1.5031085 ↗
35. Lloyd, D. et al. Band gap engineering with ultralarge biaxial strains in suspended monolayer MoS2. Nano Lett. 16, 5836–5841 (2016).10.1021/acs.nanolett.6b02615 ↗
36. Bertolazzi, S., Brivio, J. & Kis, A. Stretching and breaking of ultrathin MoS2. ACS Nano 5, 9703–9709 (2011).10.1021/nn203879f ↗
37. Lee, C., Wei, X., Kysar, J. W. & Hone, J. Measurement of the elastic properties and intrinsic strength of monolayer graphene. Science 321, 385–388 (2008).10.1126/science.1157996 ↗
38. Castellanos-Gomez, A. et al. Elastic properties of freely suspended MoS2 nanosheets. Adv. Mater. 24, 772–775 (2012).10.1002/adma.201103965 ↗
39. Li, Z. et al. Efficient strain modulation of 2D materials via polymer encapsulation. Nat. Commun. 11, 1151 (2020).10.1038/s41467-020-15023-3 ↗
40. Dimple, Jena, N. & De Sarkar, A. Compressive strain induced enhancement in thermoelectric-power-factor in monolayer MoS2 nanosheet. J. Phys. Condens. Matter 29, 225501 (2017).10.1088/1361-648X/aa6cbc ↗
41. Fichter, W. B. Some solutions for the large deflections of uniformly loaded circular membranes. NASA Tech. Pap 3658, 13–16 (1997).
42. Yang, M. M., Kim, D. J. & Alexe, M. Flexo-photovoltaic effect. Science 360, 904–907 (2018).10.1126/science.aan3256 ↗
43. Huang, Y. et al. An efficient route to prepare suspended monolayer for feasible optical and electronic characterizations of two-dimensional materials. InfoMat 4, e12274 (2022).10.1002/inf2.12274 ↗
44. Lee, J. U. et al. Strain-shear coupling in bilayer MoS. Nat. Commun. 8, 1–7 (2017).10.1038/s41467-017-01487-3 ↗
45. Çakıroğlu, O., Island, J. O., Xie, Y., Frisenda, R. & Castellanos‐Gomez, A. An automated system for strain engineering and straintronics of 2D materials. Adv. Mater. Technol. 8, 2201091 (2023).10.1002/admt.202201091 ↗
46. Mootheri, V. et al. Understanding ambipolar transport in MoS2 field effect transistors: the substrate is the key. Nanotechnology 32, 135202 (2021).10.1088/1361-6528/abd27a ↗
47. Drüppel, M., Deilmann, T., Krüger, P. & Rohlfing, M. Diversity of trion states and substrate effects in the optical properties of an MoS2 monolayer. Nat. Commun. 8, 1–7 (2017).10.1038/s41467-017-02286-6 ↗
48. Lu, C. P., Li, G., Mao, J., Wang, L. M. & Andrei, E. Y. Bandgap, mid-gap states, and gating effects in MoS2. Nano Lett. 14, 4628–4633 (2014).10.1021/nl501659n ↗
49. Ochedowski, O. et al. Effect of contaminations and surface preparation on the work function of single layer MoS2. Beilstein J. Nanotechnol. 5, 291–297 (2014).10.3762/bjnano.5.32 ↗
50. Sun, D. et al. Ultrafast hot-carrier-dominated photocurrent in graphene. Nat. Nanotechnol. 7, 114–118 (2012).10.1038/nnano.2011.243 ↗
51. Lee, C., Hong, J., Lee, W. R., Kim, D. Y. & Shim, J. H. Density functional theory investigation of the electronic structure and thermoelectric properties of layered MoS2, MoSe2 and their mixed-layer compound. J. Solid State Chem. 211, 113–119 (2014).10.1016/j.jssc.2013.12.012 ↗
52. Siao, M. D. et al. Two-dimensional electronic transport and surface electron accumulation in MoS2. Nat. Commun. 9, 1–12 (2018).10.1038/s41467-018-03824-6 ↗
53. Jahangir, I., Koley, G. & Chandrashekhar, M. V. S. Back gated FETs fabricated by large-area, transfer-free growth of a few layer MoS2 with high electron mobility. Appl. Phys. Lett. 110, 182108 (2017).10.1063/1.4982595 ↗
54. Dobusch, L. et al. Electric field modulation of thermovoltage in single-layer MoS2. Appl. Phys. Lett. 105, 253103 (2014).10.1063/1.4905014 ↗
55. Ashcroft, N. & Mermin, D. Solid State Physics (Thomson Learning Inc., 1976).
56. Joo, M. K. et al. Electron excess doping and effective Schottky barrier reduction on the MoS2/h-BN heterostructure. Nano Lett. 16, 6383–6389 (2016).10.1021/acs.nanolett.6b02788 ↗
57. Li, L. et al. Raman shift and electrical properties of MoS2 bilayer on boron nitride substrate. Nanotechnology 26, 295702 (2015).10.1088/0957-4484/26/29/295702 ↗