Discovery of Clustered-P1 Borophene and Its Application as the Lightest High-Performance Transistor

Abstract

The two-dimensional network of boron atoms (borophene) has attracted attention for its ultralow molar mass and remarkable polymorphism. Synthesized polymorphs of borophene (striped, β 12 , χ 3 , and honeycomb), so far, are all found to be metallic. Employing a genetic algorithm-based structure searching technique, here we discover an allotrope, clustered-P1, which is located very close to the global energy minimum. Clustered-P1 exhibits a bulk silicon-like band gap (1.08 eV) with symmetric effective masses (∼0.2 m 0 ) for electrons and holes along the transport direction. Phonon dispersion and beyond room-temperature ab initio molecular dynamics studies further confirm its excellent dynamic and structural stability. Since two-dimensional semiconductors are promising silicon alternatives for complementary metal-oxide semiconductor (CMOS) technology extension, we further investigate the characteristics of clustered-P1-based transistors using self-consistent quantum transport models for channel lengths of 10−3 nm. The performance of these devices has been found to be balanced for p-and n-type transistors and meets the requirements of the International Roadmap for Devices and Systems (IRDS). Our study may aid in the experimental realization of the lightest highperformance transistor.

First-Principles Particle-Swarm Structure Calculations on Metal Substrate Modulated Monolayer to Bilayer Borophene Crystalline Structures toward Nanoelectronics

“…The AIMD calculations (Figure S15) indicate that geometrical structures of δ 3 β 12 , BL-α 5 , and IH-BS remain intact at 500 K, and don’t collapse until the temperature reaches 1000, 2000, and 1500 K, respectively. Therefore, such semiconducting properties and excellent stability make BL-α 5 and IH-BS borophene a promising material for nanoelectronics. ,, Note that trivial imaginary frequencies are observed around the Γ point, partially due to the fairly planar potential surface in the vicinity of their ground state . In particular, the ground state of IH-BS is antiferromagnetic and the spin-charge density is shown in Figure S16, consistent with the studies in literature .…”

“…The allotropic forms of boron, featured with attractive electron delocalization, have gained wide research interest in past decades, including three-dimensional (3D) α- and β-rhombohedral boron bulk, two-dimensional (2D) nanosheet, one-dimensional (1D) nanostructure, and zero-dimensional (0D) clusters. , Among them, 2D borophene, analog to graphene, is particularly intriguing with structural polymorphism , and versatile electronic and magnetic characteristics, including metallicity, semiconductivity, , Dirac fermions, , and superconductivity, exhibiting potential for nanoelectronics applications, such as field effect transistors. ,, Over the past decades, extensive theoretical works have reported the stable structures and possible growth mechanism of monolayer borophene on the metal substrate. − Meanwhile, a series of monolayer borophenes have been synthesized experimentally on multiple metal substrates, such as β 12 and χ 3 sheet on Ag(111), δ 3 on Al(111), χ 6 on Ir(111), β 13 on Cu(100), borophenes with hexagon hole density η of 1/5 on Cu(111), and α 5 (η = 1/12) on Au(111), confirming the substrate-modulated polymorphic structures of monolayer borophene.…”

Borophenes: monolayer, bilayer and heterostructures

“…Borophene has attracted widespread attention in the field of two-dimensional (2D) materials since it was first synthesized in 2015. 1 It is a 2D material made entirely of boron atoms, which have important potential applications in electronics, [2][3][4] energy storage, [5][6][7][8] transport, 9 catalysis, [10][11][12] plasmonics, 13,14 superconductivity, [15][16][17][18] sensors, [19][20][21] etc. In addition, the 2D metallic properties, 1,22 such as Dirac Fermions, 23 ideal flexibility and strength, 24 antiferromagnetism 25 and excellent electronic, 26,27 gas-sensing 28 and transport 9 properties of borophene, have also attracted widespread attention from researchers.…”

“…Researchers are also exploring the use of borophene in transistors. Some special borophene phases and hydrogenated borophene exhibit semiconducting properties, 45,46 which make borophene transistors a reality, [2][3][4]29,47,48 and borophene could be utilized to produce faster and more efficient transistors than those currently available. Borophene is also being studied for use in batteries, due to the large surface zone and exceptional conductance making it an ideal material for use in electrodes, which are critical components of batteries and other energy storage devices.…”

“…10 And, the excellent photoresponse properties of borphene make it a suitable candidate material for photodetectors. 3 Topological Dirac semimetals display a unique electronic structure and have broad application prospects in the fields of electronic devices and semiconductors. Graphene is a typical lightweight Dirac material, and many novel physical phenomena and electronic properties are caused by Dirac cones.…”