[1] R Schaller. Moore's law: past, present and future. IEEE Spectrum, 34, 52(1997).

[2] D J Frank, R H Dennard, E Nowak et al. Device scaling limits of Si MOSFETs and their application dependencies. Proc IEEE, 89, 259(2001).

[3] D Sarkar, X J Xie, W Liu et al. A subthermionic tunnel field-effect transistor with an atomically thin channel. Nature, 526, 91(2015).

[4] A J Arnold, A Razavieh, J R Nas et al. Mimicking neurotransmitter release in chemical synapses via hysteresis engineering in MoS₂ transistors. ACS Nano, 11, 3110(2017).

[5] Y J Gong, G Shi, Z H Zhang et al. Direct chemical conversion of graphene to boronand nitrogen-and carbon-containing atomic layers. Nat Common, 5, 3193(2014).

[6] Y L Xie, B Lian, B Jäck et al. Spectroscopic signatures of many-body correlations in magic-angle twisted bilayer graphene. Nature, 572, 101(2019).

[7] L F Li, W Liu, A Y Gao et al. Plasmon excited ultrahot carriers and negative differential photoresponse in a vertical graphene van der Waals heterostructure. Nano Lett, 19, 3295(2019).

[8] K S Novoselov, A K Geim, S V Morozov et al. Two-dimensional gas of massless Dirac fermions in graphene. Nature, 438, 197(2005).

[9] Y B Zhang, Y W Tan, H L Stormer et al. Experimental observation of the quantum Hall effect and Berry's phase in graphene. Nature, 438, 201(2005).

[10] C Lee, X D Wei, J W Kysar et al. Measurement of the elastic properties and intrinsic strength of monolayer graphene. Science, 321, 385(2008).

[11] Y P Liu, I Yudhistira, M Yang et al. Phonon-mediated colossal magnetoresistance in graphene/black phosphorus heterostructures. Nano Lett, 18, 3377(2018).

[12] S Y Huang, G W Zhang, F R Fan et al. Strain-tunable van der Waals interactions in few-layer black phosphorus. Nat Common, 10, 2447(2019).

[13] K Chaudhary, M Tamagnone, M Rezaee et al. Engineering phonon polaritons in van der Waals heterostructures to enhance in-plane optical anisotropy. Sci Adv, 5, eaau7171(2019).

[14] J M Kim, S S Baik, S H Ryu et al. Observation of tunable band gap and anisotropic Dirac semimetal state in black phosphorus. Science, 349, 723(2015).

[15] R M Peng, K Khaliji, N Youngblood et al. Midinfrared electro-optic modulation in few-layer black phosphorus. Nano Lett, 17, 6315(2017).

[16] Z Liu, Y G Gong, W Zhou et al. Ultrathin high-temperature oxidation-resistant coatings of hexagonal boron nitride. Nat Commun, 4, 2541(2013).

[17] E X Wu, Y Xie, J Zhang et al. Dynamically controllable polarity modulation of MoTe₂ field-effect transistors through ultraviolet light and electrostatic activation. Sci Adv, 5, eaav3430(2019).

[18] H J Park, R Y J Tay, X Wang et al. Double-spiral hexagonal boron nitride and shear strained coalescence boundary. Nano Lett, 19, 4229(2019).

[19] L Song, L J Ci, H Lu et al. Large scale growth and characterization of atomic hexagonal boron nitride layers. Nano Lett, 10, 3209(2010).

[20] L J Ci, L Song, C J Jin et al. Atomic layers of hybridized boron nitride and graphene domains. Nat Mater, 9, 430(2010).

[21] Y G Gong, J H Lin, X L Wang et al. Vertical and in-plane heterostructures from WS₂/MoS₂ monolayers. Nat Mater, 13, 1135(2014).

[22] Y G Gong, Z Liu, A R Lupini et al. Band gap engineering and layer-by-layer mapping of selenium doped molybdenum disulfide. Nano Lett, 14, 442(2014).

[23] Y Ma, P M Ajayan, Y J Gong et al. Recent advances in synthesis and applications of 2D junctions. Small, 14, 1801606(2018).

[24] Y C Lin, S S Li, H P Komsa et al. Revealing the atomic defects of WS₂ governing its distinct optical emissions. Adv Funct Mater, 28, 1704210(2017).

[25] L F Sun, W S Leong, S Z Yang et al. Concurrent synthesis of high-performance monolayer transition metal disulfdes. Adv Funct Mater, 27, 1605896(2017).

[26] Y Zhou, H J Jang, J M Woods et al. Direct synthesis of large-scale WTe₂ thin films with low thermal conductivity. Adv Funct Mater, 27, 1605928(2017).

[27] Y D Zhao, J S Qiao, P Yu et al. Extraordinarily strong interlayer interaction in 2D layered PtS₂. Adv Mater, 28, 2399(2017).

[28] J X Wu, Y J Liu, Z J Tan et al. Chemical patterning of high-mobility semiconducting 2D Bi₂O₂Se crystals for integrated optoelectronic devices. Adv Mater, 29, 1704060(2017).

[29] L Li, Y C Guo, Y P Sun et al. A general method for the chemical synthesis of large-scale, seamless transition metal dichalcogenide electronics. Adv Mater, 30, 1706215(2018).

[30] Y H Huan, J P Shi, X L Zou et al. Vertical 1T-TaS₂ synthesis on nanoporous gold for high-performance electrocatalytic applications. Adv Mater, 30, 1705916(2018).

[31] T Zhang, L Fu. Controllable chemical vapor deposition growth of two-dimensional heterostructures. Chem, 4, 671(2018).

[32] R J Xu, H Jang, M H Lee et al. Vertical MoS₂ double-layer memristor with electrochemical metallization as an atomic-scale synapse with switching thresholds approaching 100 mV. Nano Lett, 19, 2411(2019).

[33] Y B Zhu, Y J Li, R A Arefe et al. Monolayer molybdenum disulfide transistors with single-atomthick gates. Nano Lett, 18, 3807(2018).

[34] S Kim, Z P Yao, J M Lim et al. Atomic-scale observation of electrochemically reversible phase transformations in SnSe₂ single crystals. Adv Mater, 30, 1804925(2018).

[35] C S Liu, X Yan, X F Song et al. A semi-floating gate memory based on van der Waals heterostructures for quasi-non-volatile applications. Nat Nano, 13, 404(2018).

[36] A Y Gao, J W Lai, Y J Wang et al. Observation of ballistic avalanche phenomena in nanoscale vertical InSe/BP heterostructures. Nat Nano, 14, 217(2019).

[37] S Das, J A Robinson, M Dubey et al. Beyond graphene: progress in novel two dimensional materials and van der Waals solids. Annu Rev Mater Res, 45, 1(2015).

[38] V K Sangwan, M E Beck, A Henning et al. Self-aligned van der Waals heterojunction diodes and transistors. Nano Lett, 18, 1421(2018).

[39] D Lembke, A Kis. Breakdown of high-performance monolayer MoS₂ transistors. ACS Nano, 6, 10070(2012).

[40] S Manzeli, D Ovchinnikov, D Pasquier et al. 2D transition metal dichalcogenides. Nat Rev Mater, 2, 17033(2017).

[41] W Luo, M J Zhu, G Peng et al. Carrier modulation of ambipolar few-layer MoTe₂ transistors by MgO surface charge transfer doping. Adv Mater, 28, 1704539(2018).

[42] A Avsar, K Marinov, E G Marin et al. Reconfgurable diodes based on vertical WSe₂ transistors with van der Waals bonded contacts. Adv Mater, 30, 17072000(2018).

[43] S Kim, J Maassen, J Lee et al. Interstitial Mo-assisted photovoltaic effect in multilayer MoSe₂ phototransistors. Adv Mater, 30, 1705542(2018).

[44] S H Song, M K Joo, M Neumann et al. Probing defect dynamics in monolayer MoS₂ via noise nanospectroscopy. Nat Commun, 8, 2121(2017).

[45] H Tian, Q S Guo, Y J Xie et al. Anisotropic black phosphorus synaptic device for neuromorphic applications. Adv Mater, 28, 4991(2016).

[46] D Jena, K Banerjee, G H Xing et al. 2D crystal semiconductors: Intimate contacts. Nat Mater, 13, 2640(2014).

[47] L P Xu, P Zhang, H N Jiang et al. Large-scale growth and field-effect transistors electrical engineering of atomic-layer SnS₂. Small, 15, 1904116(2019).

[48] G H Han, D L Duong, D H Keum et al. Van der Waals metallic transition metal dichalcogenides. Chem Rev, 118, 6297(2018).

[49] D S Schulman, A J Arnold, S Das. Contact engineering for 2D materials and devices. Chem Soc Rev, 47, 3037(2018).

[50] M Baranowski, A Surrente, L Klopotowski et al. Probing the interlayer exciton physics in a MoS₂/MoSe₂/MoS₂ van der Waals heterostructure. Nano Lett, 17, 6360(2017).

[51] M A Islam, J H Kim, A Schropp et al. Centimeter-scale 2D van der Waals vertical heterostructures integrated on deformable substrates enabled by gold sacrificial layer-assisted growth. Nano Lett, 17, 6157(2017).

[52] C Y Yan, C H Gong, P H Wang et al. 2D group IVB transition metal dichalcogenides. Adv Funct Mater, 28, 1803305(2018).

[53] D Voiry, A Mohite, M Chhowalla. Phase engineering of transition metal dichalcogenides. Chem Soc Rev, 44, 2702(2015).

[54] X S Wang, Z G Song, W Wen et al. Potential 2D materials with phase transitions: structure, synthesis, and device applications. Adv Mater, 31, 1804682(2019).

[55] M S Stark, K L Kuntz, S J Martens et al. Intercalation of layered materials from bulk to 2D. Adv Mater, 31, 1808213(2019).

[56] H Li, S C Ruan, Y J Zeng. Intrinsic van der Waals magnetic materials from bulk to the 2D limit: new frontiers of spintronics. Adv Mater, 31, 1900065(2019).

[57] A Allain, J H Kang, K Banerjee et al. Electrical contacts to two-dimensional semiconductors. Nat Mater, 14, 1195(2015).

[58] J Kang, W Liu, D Sarkar. Computational study of metal contacts to monolayer transition­metal dichalcogenide semiconductors. Phys Rev X, 4, 031005(2014).

[59] J C Ranuárez, M J Deen, C H Chen. A review of gate tunneling current in MOS devices. Microelectron Reliab, 46, 1939(2016).

[60] Y Liu, J Guo, E B Zhu et al. Approaching the Schottky–Mott limit in van der Waals metal–semiconductor junctions. Nature, 557, 696(2018).

[61] C D English, G Shine, V E Dorgan et al. Improved contacts to MoS₂ transistors by ultra-high vacuum metal deposition. Nano Lett, 16, 3824(2016).

[62] K Stokbro, M Engelund, A Blom. Atomic­scale model for the contact resistance of the nickel­graphene interface. Phys Rev B, 85, 165442(2012).

[63] I Popov, G Seifert, D Tománek. Designing electrical contacts to MoS₂ monolayers: a computational study. Phys Rev Lett, 108, 156802(2012).

[64] W Liu, J H Kang, W Cao et al. High­ performance few­ layer­ MoS₂ field-effect-transistor with record low contact­resistance. IEEE Int Electron Devices Meet, 19.4. 1(2013).

[65] L Wang, I Meric, P Y Huang et al. One-dimensional electrical contact to a two-dimensional material. Science, 342, 614(2013).

[66] X Cui, G H Lee, Y D Kim et al. Multi-terminal transport measurements of MoS₂ using a van der Waals heterostructure device platform. Nat Mater, 10, 534(2015).

[67] Y Chai, R Ionescu, S S Su et al. Making one-dimensional electrical contacts to molybdenum disulfid-based heterostructures through plasma etching. Phys Status Solidi A, 213, 1358(2016).

[68] Y Matsuda, W Q Deng, W A Goddard. Contact resistance for “end-contacted” metal−graphene and metal−nanotube interfaces from quantum mechanics. J Phys Chem C, 114, 17845(2010).

[69] B Karpiak, A Dankert, A W Cummings et al. 1D ferromagnetic edge contacts to 2D graphene/h-BN heterostructures. 2D Mater, 5, 014001(2017).

[70] Y Zhang, L Yin, J W Chu et al. Edge-epitaxial growth of 2D NbS₂-WS₂ lateral metal-semiconductor heterostructures. Adv Mater, 30, 1803665(2018).

[71] Y J Gong, S D Lei, G L Ye et al. Two-step growth of two-dimensional WSe₂/MoSe₂ heterostructures. Nano Lett, 15, 6135(2015).

[72] Y G Gong, Z Lin, G L Ye et al. Tellurium-assisted low-temperature synthesis of MoS₂ and WS₂ monolayers. ACS Nano, 9, 11658(2015).

[73] Q Q Ji, C Li, J L Wang et al. Metallic vanadium disulfide nanosheets as a platform material for multifunctional electrode applications. Nano Lett, 17, 4908(2017).

[74] J D Zhou, J H Lin, X W Huang et al. A library of atomically thin metal chalcogenides. Nature, 556, 358(2018).

[75] W S Leong, Q Q Ji, N N Mao et al. Synthetic lateral metal–semiconductor heterostructures of transition metal disulfides. J Am Chem Soc, 140, 12354(2018).

[76] C S Lee, S J Oh, H Heo et al. Epitaxial van der Waals contacts between transition-metal dichalcogenide monolayer polymorphs. Nano Lett, 19, 1814(2019).

[77] R X Wu, Q Y Tao, W Q Dang et al. van der Waals epitaxial growth of atomically thin 2D metals on dangling-bond-free WSe₂ and WS₂. Adv Funct Mater, 29, 1806611(2019).

[78] Y Y Jin, Z Y Zeng, Z W Xu et al. Synthesis and transport properties of degenerate p-type Nb-doped WS₂ monolayers. Chem Mater, 31, 3534(2019).

[79] J Suh, T E Park, D Y Lin et al. Doping against the native propensity of MoS₂: degenerate hole doping by cation substitution. Nano Lett, 14, 6976(2014).

[80] R Kappera, D Voiry, S E Yalcin et al. Phase-engineered low-resistance contacts for ultrathin MoS₂ transistors. Nat Mater, 13, 1128(2014).

[81] J Q Zhu, Z G Wang, H Yu et al. Argon plasma induced phase transition in monolayer MoS₂. J Am Chem Soc, 139, 10216(2017).

[82] Y J Gong, H T Yuan, C L Wu et al. Spatially controlled doping of two-dimensional SnS₂ through intercalation for electronics. Nat Nano, 13, 294(2018).

[83] W Schottky. Zur Halbleitertheorie der sperrschicht-und spitzengleichrichter. Z Phys A, 113, 367(1939).

[84] N Mott. The theory of crystal rectifers. Proc R Soc Lond A, 171, 27(1939).

[85] J Bardeen. Surface states and rectifcation at a metal semi-conductor contact. Phys Rev, 71, 717(1947).

[86] S Das, H Y Chen, A V Penumatcha et al. High performance multi-layer MoS₂ transistors with scandium contacts. Nano Lett, 13, 100(2013).

[87] Y Wang, J C Kim, R J Wu et al. Van der Waals contacts between three-dimensional metals and two-dimensional semiconductors. Nature, 568, 70(2019).

[88]

[89] Y Khatami, H Li, C Xu et al. Metal­-to-­multilayer-­graphene contact—Part II: analysis of contact resistance. IEEE Trans Electron Devices, 59, 2453(2012).

[90] Y Khatami, H Li, C Xu et al. Metal­-to-­multilayer-­graphene contact—Part I: contact resistance modeling. IEEE Trans Electron Devices, 59, 2444(2012).

[91] M Zhao, Y Ye, Y Han et al. Large-scale chemical assembly of atomically thin transistors and circuits. Nat Nano, 11, 954(2016).

[92] W Hong, G W Shim, S Y Yang et al. Improved electrical contact properties of MoS₂-graphene lateral heterostructure. Adv Funct Mater, 29, 1807550(2019).

[93] W S Leong, C T Nai, J T L Tong. What does annealing do to metal-graphene contacts. Nano Lett, 14, 3840(2014).

[94] F Léonard, A A Talin. Electrical contacts to one- and two-dimensional nanomaterials. Nat Nano, 6, 773(2011).

[95] V Heine. Theory of surface states. Phys Rev, 138, A1689(1965).

[96] L N Liu, J X Wu, L Y Wu et al. Phase-selective synthesis of 1T’ MoS₂ monolayers and heterophase bilayers. Nat Mater, 17, 1108(2018).

[97] J Y Zheng, X X Yan, Z X Lu et al. High-mobility multilayered MoS₂ flakes with low contact resistance grown by chemical vapor deposition. Adv Mater, 29, 1604540(2017).

[98] C Gong, L Colombo, R M Wallace et al. The unusual mechanism of partial fermi level pinning at metal –MoS₂ interfaces. Nano Lett, 14, 1714(2014).

[99] W A Saidi. Trends in the adsorption and growth morphology of metals on the MoS₂(001) surface. Cryst Growth Des, 15, 3190(2015).

[100] L J Meng, Y Ma, K P Si et al. Recent advances of phase engineering in group VI transition metal dichalcogenides. Tungsten, 1, 46(2019).

[101] J Li, X D Yang, Y Liu et al. General synthesis of two-dimensional van der Waals heterostructure arrays. Nature, 579, 368(2020).