Strain engineering the electronic properties of the type-II CdO/MoS2 van der Waals heterostructure

Rational design of a direct Z-scheme β-AsP/SiC van der Waals heterostructure as an efficient photocatalyst for overall water splitting under wide solar spectrum

“…5(a) shows that there is a large potential difference (Δ V ) at the β-AsP/SiC heterojunction interface and the electrostatic potential of the SiC layer is lower than that of the β-AsP layer along the Z -direction, corresponding to the built-in electric field from SiC to β-AsP layer. This is consistent with the patterns that have been reported, such as GaP/GaAs, 57 g-C 6 N 6 /GaS, 58 GaN/InS, 59 CdO/MoS 2 , 60 PtSe 2 /WS 2 , 61 GaSe/g-C 6 N 6 , 62 and PtS 2 /g-C 3 N 4 . 23 The large potential drop is vital for photogenerated electron and hole separation.…”

“…When the β-AsP/SiC heterojunction absorbs enough energy under the irradiation of sunlight, the electron in the valence band of both β-AsP and SiC layers will be excited into the conduction band. Unlike type-II heterojunctions, 48,50,[58][59][60][61][62] the direction of the built-in electric field is from SiC to β-AsP, which is the most significant distinction between the two forms of heterojunctions, that is to say, due to the built-in electric field from SiC to β-AsP, the photogenerated electrons in the CBM of β-AsP will recombine with the photogenerated holes in the VBM of the SiC layer. Thus, the photogenerated electrons accumulate in the CBM of SiC layer and the photogenerated holes gather in the VBM of β-AsP layer, suggesting that the photogenerated carriers are effectively separated in different semiconductors.…”

Strain-Induced Enhanced Performance in 2D C2N/MoS2 Heterostructures for Photocatalytic Water Splitting: A Meta-GGA Study

“…The presence of the direct band gap of 1.35 eV and type-II band alignment makes it easier to realize the electronic transition, which are useful for enhanced carrier mobility, thus providing superior performance for photocatalytic applications as compared to the MoS 2 /ZnO heterostructure having an indirect band gap of 1.6 eV . Similarly, the impact of mechanical strain on the photocatalytic water splitting performance of the CdO/MoS 2 heterostructure has been analyzed through first-principles DFT calculations, which exhibit high carrier mobility even in the presence of large biaxial strain, and the band edge positions can be effectively modulated by biaxial strain engineering . The observations are also consistent with our calculations on the strain-induced band alignment in the C 2 N/MoS 2 heterostructure for vertical, biaxial, and uniaxial strain configurations, which indicates the enhancement of band edge positions, spanning the water redox potential values, with compressive uniaxial/biaxial and tensile vertical strain.…”

PtS2/GeC van der Waals heterostructure: a promising direct Z-scheme photocatalyst with high solar-to-hydrogen energy conversion efficiency for overall water splitting under acidic, alkaline, and neutral conditions and in large-strain regions

“…However, in traditional type-II heterojunction photocatalysts, the photogenerated electrons and holes with the stronger reduction and oxidation abilities will move continuously under the driving force of conduction band offset and valence band offset respectively, and the materials involved in the photocatalytic water splitting do not use their higher redox potential. 3,36,[42][43][44] The catalytic capability of the type-II heterojunction photocatalysts is directly influenced by their band gaps, necessitating a larger value than the minimum band gap of 1.23 eV for overall water splitting, such as AsP/GaSe (1.924 eV), 36 GaN/InS (1.91 eV), 42 GaSe/g-C 6 N 6 (2.16 eV), 43 and CdO/MoS 2 (1.35 eV). 44 The identification of the Z-scheme heterojunction photocatalysts has effectively addressed this challenge.…”