Abstract:We report a combination of experimental results with density functional theory (DFT) calculations to understand electronic structure of indium tin oxide and molybdenum disulfide (ITO–MoS2) interface. Our results indicate ITO and MoS2 conform an n-type Schottky barrier of c.a. − 1.0 eV due to orbital interactions; formation of an ohmic contact is caused by semiconducting and metal behavior of ITO as a function of crystal plane orientation. ITO introduces energy levels around the Fermi level in all interface mod… Show more
“…Cross-section scanning electron microscopy (SEM) images present visual aspects of the ITO/MoS 2−x Se x /ITO array (Fig. 1 c), confirming a well-defined and sharp interface formation as previously reported 10 , 25 and of comparable quality to those obtained by CVD methods 26 . Figure 1 ( a , b ) Time-of-flight secondary ion mass spectrometry depth profile measurements for positive and negative ions, respectively.…”
Section: Resultssupporting
confidence: 87%
“…From the approaches mentioned, heterostructure formation has stood as a potential route to attain new mixed phases with enhanced piezoelectric properties 7 , improved catalytic activity 8 , band gap engineering 9 , and reduced contact resistance. The latter, for example, has been determined by the electronic structure calculations of ITO-MoS 2 with a n -type Schottky barrier height ( Φ n ) of ~ 0.2 eV 10 . However, the research on mixed phases based on TMDC heterostructures still requires an extended understanding of their properties and potential improvements in their fabrication.…”
We present the fabrication of a MoS2−xSex thin film from a co-sputtering process using MoS2 and MoSe2 commercial targets with 99.9% purity. The sputtering of the MoS2 and MoSe2 was carried out using a straight and low-cost magnetron radio frequency sputtering recipe to achieve a MoS2−xSex phase with x = 1 and sharp interface formation as confirmed by Raman spectroscopy, time-of-flight secondary ion mass spectroscopy, and cross-sectional scanning electron microscopy. The sulfur and selenium atoms prefer to distribute randomly at the octahedral geometry of molybdenum inside the MoS2−xSex thin film, indicated by a blue shift in the A1g and E1g vibrational modes at 355 cm−1 and 255 cm−1, respectively. This work is complemented by computing the thermodynamic stability of a MoS2−xSex phase whereby density functional theory up to a maximum selenium concentration of 33.33 at.% in both a Janus-like and random distribution. Although the Janus-like and the random structures are in the same metastable state, the Janus-like structure is hindered by an energy barrier below selenium concentrations of 8 at.%. This research highlights the potential of transition metal dichalcogenides in mixed phases and the need for further exploration employing low-energy, large-scale methods to improve the materials’ fabrication and target latent applications of such structures.
“…Cross-section scanning electron microscopy (SEM) images present visual aspects of the ITO/MoS 2−x Se x /ITO array (Fig. 1 c), confirming a well-defined and sharp interface formation as previously reported 10 , 25 and of comparable quality to those obtained by CVD methods 26 . Figure 1 ( a , b ) Time-of-flight secondary ion mass spectrometry depth profile measurements for positive and negative ions, respectively.…”
Section: Resultssupporting
confidence: 87%
“…From the approaches mentioned, heterostructure formation has stood as a potential route to attain new mixed phases with enhanced piezoelectric properties 7 , improved catalytic activity 8 , band gap engineering 9 , and reduced contact resistance. The latter, for example, has been determined by the electronic structure calculations of ITO-MoS 2 with a n -type Schottky barrier height ( Φ n ) of ~ 0.2 eV 10 . However, the research on mixed phases based on TMDC heterostructures still requires an extended understanding of their properties and potential improvements in their fabrication.…”
We present the fabrication of a MoS2−xSex thin film from a co-sputtering process using MoS2 and MoSe2 commercial targets with 99.9% purity. The sputtering of the MoS2 and MoSe2 was carried out using a straight and low-cost magnetron radio frequency sputtering recipe to achieve a MoS2−xSex phase with x = 1 and sharp interface formation as confirmed by Raman spectroscopy, time-of-flight secondary ion mass spectroscopy, and cross-sectional scanning electron microscopy. The sulfur and selenium atoms prefer to distribute randomly at the octahedral geometry of molybdenum inside the MoS2−xSex thin film, indicated by a blue shift in the A1g and E1g vibrational modes at 355 cm−1 and 255 cm−1, respectively. This work is complemented by computing the thermodynamic stability of a MoS2−xSex phase whereby density functional theory up to a maximum selenium concentration of 33.33 at.% in both a Janus-like and random distribution. Although the Janus-like and the random structures are in the same metastable state, the Janus-like structure is hindered by an energy barrier below selenium concentrations of 8 at.%. This research highlights the potential of transition metal dichalcogenides in mixed phases and the need for further exploration employing low-energy, large-scale methods to improve the materials’ fabrication and target latent applications of such structures.
“…[29] Nevertheless, the intersection of energy bands with the Fermi level as the MoS 2 /MoSe 2 heterojunction bends confirms the transition from a semiconductor to a semimetal character predicted with the pDOS happening between the M, K, and the Γ points of the Brillouin zone, and attributed to metallic d-orbitals from molybdenum and metal-metal interaction. [30] The computed variation of the bandgap as the heterojunction bends, also indicates that band alignment could be achieved even at small deformation angles, which can induce large areas of electrondonor acceptor ideal for catalytic properties or electronic modulation for supercapacitor applications as reported by Li et al [13]…”
We present a theoretical study for MoS2/MoSe2 Van der Waals heterojunction in the armchair direction, and periodicity in the y-direction, under the mechanical deformation process to explore electronic structure vs. curvature angle. Our findings reveal that the heterojunction maintains chemical stability, even under high deformation, and the bandgap of the heterojunction is inversely proportional to curvature angle; the shift from semiconductor—with a bandgap of 0.8 eV—to semimetal occurs at deformation angles as low as 5°, having a gapless material. The mentioned transition corresponds mainly to distortion of half-filled molybdenum d-orbitals and chalcogen–chalcogen p-orbitals overlapping near the Fermi level.
Graphical abstract
“… monolayers have already been experimentally synthesized to be used for the 2D nanodevices and to perform outstanding features. [ 4,5,16,17 ] is also a valleytronic material with valley‐contrasting transport properties [ 18,19 ] and strong potential in 2D‐material‐based computing electronics. [ 20,21 ] The 2D lattice system of can be cut into quausi‐1D nanoribbons with the typical edge termination of zigzag and armchair.…”
Herein, the spin‐polarized edge‐state transport properties in L‐shaped zigzag nanodevice () are investigated based on tight‐binding model, Green's function method, and ballistic transport theory. The spin conductance and spin polarization are calculated by considering external exchange field and electric field. It is shown in the results that the spin conductance is closely related to the configuration of atomic non‐consistence on the edge of . Meanwhile, the spin conductance is determined by the spin channel opening on the edge, which can be modulated by external fields. The configuration characteristic and external fields give rise to effects of sublattice mismatch and spin mismatch on the edge channels, respectively. As a consequence, mismatch effects are actually employed to modulate the spin channel on the edge of , and 100% spin polarization is realized selectively. Moreover, the corresponding local density of states distributions are plotted to reveal the modulation of the spin‐resolved edge‐state and the spin‐filtering effects in the real space. These spin‐polarized edge‐state transport properties in can have potential application in various kinds of spin valves and spin filters in nanocircuits.
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