Planar penta-transition metal phosphide and arsenide as narrow-gap semiconductors with ultrahigh carrier mobility

Abstract

Searching for materials with single atom-thin as well as planar structure, like graphene and borophene, is one of the most attractive themes in two dimensional materials.Herein, using density functional theory calculations, we have proposed a series of single layer planar penta-transition metal phosphide and arsenide, i.e. TM2X4 (TM= Ni, Pd and Pt; X=P, As). According to the calculated phonon dispersion relation and elastic constants, as well as ab initio molecular dynamics simulation results, monolayers of planar penta-TM2X4 are dynamically, mechanically, and thermally stable. In addition, the band structures calculated with the screened HSE06 hybrid functional including spin-orbit coupling show that these monolayers are direct-gap semiconductors with sizeable band gaps ranging from 0.14 eV to 0.69 eV. Besides, the optical properties in 2 these monolayers are further investigated, where strong in-plane optical absorption with wide spectral range has been revealed. Our results indicate that planar penta-TM2X4 monolayers are interesting narrow gap semiconductors with excellent optical properties, and may find potential applications in photoelectronics.

The novel two-dimensional photocatalyst SnN3with enhanced visible-light absorption for overall water splitting

“…Electrostatic potential indicates the minimum energy that electron must absorb when it escapes from a material, which shows relationship with chemical stability [18,[20][21][22]. Figure 3 Water splitting is a clean and effective way of oxygen and hydrogen production.…”

“…Based on the previous achievements [18,[20][21][22], our SnN3 start from the SnP3 monolayer (R-3m space group), replacing the P atoms into N atoms then proceeding geometry optimization to minimize the remnant force and stress. Figure 1 (a As results, the formation energy from SnP3 to SnN3 reaches -220 meV/atom, comparable with Pt dope in MoS2 monolayer (-230 meV per atom) [30] and in a low position of the formation energy alignment [7].…”

“…Besides, the GeP3 monolayer also has better carrier mobility (10 3 cmV -1 s -1 ) than MoS2 [18], but much smaller than monolayer and bilayer SnP3. Layered SnP3 is a new type 2D material predicted from GeP3 with ultrahigh carrier mobility (1.15×10 4 cmV -1 s -1 ) and great light absorption capacity [18][19][20][21][22]. Compared with other materials like GeS2 (0.52 Jm -2 ) [23,24], NaSnP (0.81 Jm -2 ) [25], GeP3 (0.91 Jm -2 ) [26], GaN2 (1.09 Jm -2 ) [27], InP3 (1.32 Jm -2 ) [13] and graphene (0.36 Jm -2 ) [28,29], the calculated cleavage energy of 1L and 2L SnP3 are 0.57 Jm -2 and 0.38 Jm -2 [20].…”

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

“…Very recently, a series of 2D pnictides (nitrides, phosphides and arsenides) semiconductors have been theoretically proposed as novel 2D semiconductors with high carrier mobilities (~10 3 cm 2 V -1 s -1 -10 5 cm 2 V -1 s -1 ) that are comparable or superior to those of phosphorene [14][15][16][17][18][19][20][21][22][23][24][25]. For instance, in monolayer Pt2N4 with a planar pentastructure, the electron mobility at room temperature can reach 1.1×10 5 cm 2 V -1 s -1 , comparable to that in graphene [20].…”

“…For instance, in monolayer Pt2N4 with a planar pentastructure, the electron mobility at room temperature can reach 1.1×10 5 cm 2 V -1 s -1 , comparable to that in graphene [20]. In addition to the materials with a single atomic layer thickness, such as TM2X4(TM=Ni, Pd and Pt, X=P, As) [23], most of them possess blue phosphorene-type or black phosphorene-type structural features. For example, CaP3 (CaAs3) monolayers possess similar 2D networks of puckered configurations, and the puckered polyanionic P3 2 (As3 2-) nets are derivatives of the black phosphorene (puckered arsenene) structure by removing 1/4 of the P (As) atoms.…”