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

[2] A C Ferrari, J C Meyer, V Scardaci et al. Raman spectrum of graphene and graphene layers. Phys Rev Lett, 97, 187401(2006).

[3] A K Geim, K S Novoselov. The rise of graphene. Nat Mater, 6, 183(2007).

[4] M Y Han, B Özyilmaz, Y B Zhang et al. Energy band-gap engineering of graphene nanoribbons. Phys Rev Lett, 98, 206805(2007).

[5] W J Zhu, D Neumayer, V Perebeinos et al. Silicon nitride gate dielectrics and band gap engineering in graphene layers. Nano Lett, 10, 3572(2010).

[6] K F Mak, C Lee, J Hone et al. Atomically thin MoS₂: A new direct-gap semiconductor. Phys Rev Lett, 105, 136805(2010).

[7] B Radisavljevic, A Radenovic, J Brivio et al. Single-layer MoS₂ transistors. Nat Nanotechnol, 6, 147(2011).

[8] K F Mak, K He, J Shan et al. Control of valley polarization in monolayer MoS₂ by optical helicity. Nat Nanotechnol, 7, 494(2012).

[9] L K Li, Y J Yu, G J Ye et al. Black phosphorus field-effect transistors. Nat Nanotechnol, 9, 372(2014).

[10] E S Reich. Phosphorene excites materials scientists. Nature, 506, 19(2014).

[11] G Fiori, F Bonaccorso, G Iannaccone et al. Erratum: Electronics based on two-dimensional materials. Nat Nanotechnol, 9, 1063(2014).

[12] M S Xu, T Liang, M M Shi et al. Graphene-like two-dimensional materials. Chem Rev, 113, 3766(2013).

[13] P Vogt, P de Padova, C Quaresima et al. Silicene: Compelling experimental evidence for graphenelike two-dimensional silicon. Phys Rev Lett, 108, 155501(2012).

[14] M E Dávila, L Xian, S Cahangirov et al. Germanene: A novel two-dimensional germanium allotrope akin to graphene and silicene. New J Phys, 16, 095002(2014).

[15] F F Zhu, W J Chen, Y Xu et al. Epitaxial growth of two-dimensional stanene. Nat Mater, 14, 1020(2015).

[16] Z Zhu, X Cai, S Yi et al. Multivalency-driven formation of Te-based monolayer materials: A combined first-principles and experimental study. Phys Rev Lett, 119, 106101(2017).

[17] Z H Wang, X F Zhou, X M Zhang et al. Phagraphene: A low-energy graphene allotrope composed of 5-6-7 carbon rings with distorted Dirac cones. Nano Lett, 15, 6182(2015).

[18] Y Liu, G Wang, Q S Huang et al. Structural and electronic properties of T graphene: A two-dimensional carbon allotrope with tetrarings. Phys Rev Lett, 108, 225505(2012).

[19] R H Baughman, H Eckhardt, M Kertesz. Structure-property predictions for new planar forms of carbon: Layered phases containing sp2 and sp atoms. J Chem Phys, 87, 6687(1987).

[20] N Narita, S Nagai, S Suzuki et al. Optimized geometries and electronic structures of graphyne and its family. Phys Rev B, 58, 11009(1998).

[21] G X Li, Y L Li, H B Liu et al. Architecture of graphdiyne nanoscale films. Chem Commun, 46, 3256(2010).

[22] M Q Long, L Tang, D Wang et al. Electronic structure and carrier mobility in graphdiyne sheet and nanoribbons: Theoretical predictions. ACS Nano, 5, 2593(2011).

[23] Q Song, B Wang, K Deng et al. Graphenylene, a unique two-dimensional carbon network with nondelocalized cyclohexatriene units. J Mater Chem C, 1, 38(2013).

[24] S H Zhang, J Zhou, Q Wang et al. Penta-graphene: A new carbon allotrope. PNAS, 112, 2372(2015).

[25] B Ram, H Mizuseki. Tetrahexcarbon: A two-dimensional allotrope of carbon. Carbon, 137, 266(2018).

[26] B Ram, H Mizuseki. C568: A new two-dimensional sp2–sp3 hybridized allotrope of carbon. Carbon, 158, 827(2020).

[27] G Kresse, J Furthmüller. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys Rev B, 54, 11169(1996).

[28] J P Perdew, K Burke, M Ernzerhof. Generalized gradient approximation made simple. Phys Rev Lett, 77, 3865(1996).

[29] P E Blöchl. Projector augmented-wave method. Phys Rev B, 50, 17953(1994).

[30] J Heyd, J E Peralta, G E Scuseria et al. Energy band gaps and lattice parameters evaluated with the Heyd–Scuseria–Ernzerhof screened hybrid functional. J Chem Phys, 123, 174101(2005).

[31] H J Monkhorst, J D Pack. Special points for Brillouin-zone integrations. Phys Rev B, 13, 5188(1976).

[32]

[33] J Kang, S Tongay, J Zhou et al. Band offsets and heterostructures of two-dimensional semiconductors. Appl Phys Lett, 102, 012111(2013).

[34] X Wang, Y Li, L Huang et al. Short-wave near-infrared linear dichroism of two-dimensional germanium selenide. J Am Chem Soc, 139, 14976(2017).

[35] K Zhao, Z M Wei, X W Jiang. Polarized photodetectors based on two-dimensional semiconductors. Sci China Phys Mech Astron, 63, 1(2019).

[36] Z Li, Y Lv, L Ren et al. Efficient strain modulation of 2D materials via polymer encapsulation. Nat Commun, 11, 1151(2020).

[37] D Akinwande, N Petrone, J Hone. Two-dimensional flexible nanoelectronics. Nat Commun, 5, 5678(2014).

[38] S Das, R Gulotty, A V Sumant et al. All two-dimensional, flexible, transparent, and thinnest thin film transistor. Nano Lett, 14, 2861(2014).