BaAs3: a narrow gap 2D semiconductor with vacancy-induced semiconductor–metal transition from first principles

Abstract

Searching for novel two-dimensional (2D) materials is highly desired in the field of nanoelectronics. We here propose a new 2D crystal barium tri-arsenide (BaAs3) with a series of encouraging functionalities. Being kinetically and thermally stable, the monolayer and bilayer forms of BaAs3 possess narrow indirect band gaps of 0.87 eV and 0.40 eV, respectively, with high hole mobilities on the order of ~10 3 cm 2 V -1 s -1 . The electronic properties of 2D BaAs3 can be manipulated by controlling the layer thickness. The favorable cleavage energy reveals that layered BaAs3 can be produced as a freestanding 2D material. Furthermore, by introducing vacancy defects monolayer BaAs3 can be transformed from a semiconductor to a metal. 2D BaAs3 may find promising applications in nanoelectronic devices.

DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity

“…GGA-1/2 has enhanced the band gap by 24.52%. DFT-1/2 was also used to calculate the electronic structures of 2D materials, such as Ge-based 2D compounds [155], 2D group-IV allotropes and alloys [299,300], 2D MoS 2 [301], black phosphorus [302], borophene [303], single-walled carbon nanotubes [304], Si nanowires [305], InGaN nanowires [306], InP nanowires [307], GaP and GaN nanowires [308][309][310], MoS 2 /AlN van der Waals heterostructures [311], predicted new 2D materials [156,312], 2D Si(100) surfaces [313][314][315], 2D Si(111) surfaces [316][317][318][319], 2D SiGe [320], Si 1−x Ge x nanoribbons [321], 2D perovskites [322][323][324][325], 2D hexagonal BN [326,327], 2D GaN [328], 2D BP [329], AlN nanotubes [330], ZnO nanostructures [331], III-V quantum wells [332][333][334], borophene/C 4 N 4 heterojunctions [335], HfS 2 and TiS 2 monolayers [336], 2D PtTe 2 [337], 2D InSe-based heterostructures [338]…”

Band alignment of monolayer CaP$_3$, CaAs$_3$, BaAs$_3$ and the role of $p$-$d$ orbital interactions in the formation of conduction band minima

“…We included ten valence and semicore states for Ca and Ba, 15 states for As and five valence states for P. The vacuum included for the QE and subsequent calculations was smaller than during the structural relaxation and was sufficient to contain at least 99% of the charge density in half the unit cell. We neglected spin orbit coupling in our calculations as it was shown by Tang et al 3 that including relativistic effects changes the band gap by less than 0.01 eV in monolayer BaAs 3 .…”

“…The optical and electronic properties of black phosphorus (bP), such as its high carrier mobility 1 and tunable band gap 2 , have sparked interest in the broader family of phosphorene related 2D material structures. Recently, several new 2D materials related to phosphorene and arsenene -for which a part of the As or P atoms is replaced by group II elements [3][4][5] or elements of other groups (III, IV, V) [6][7][8][9] -have been predicted. These layered materials show a combination of high carrier mobilities, moderate band gaps and good light absorption properties promising for next-generation electronic heterojunction devices like solar cells and transistors.…”

“…Although hybrid functionals alleviate the band gap problem of DFT, it is generally accepted that GW quasiparticle calculations provide the most reliable and accurate level of theory for band structure and band alignment calculations. [12][13][14][15] Here, we calculate the band gaps of the recently predicted [3][4][5] CaP 3 , CaAs 3 and BaAs 3 monolayers at the G 0 W 0 level of theory. We estimate their band alignments according to the electron affinity rule which states that the conduction band offset of a heterojunction can be obtained from the electron affinities of the individual materials.…”