structural and electronic properties of 2D-MoS 2 that
may guide synthesis and utilization in various areas. It
is found that the dopants considered in this study can
be achieved under non-equilibrium conditions with O
and P having the lowest and highest formation energy,
respectively. It is noted that O and Cl dopants induce
bandgap narrowing and at higher concentration the
system becomes insensitive to O, while it responds
to Cl up to 31%.
On the other hand, P and Se dopants induce bandgap
broadening of 2D MoS 2 and at a higher concentration above 31% the system becomes insensitive. It
was further observed that co-dopants Cl-P, O-P, and
O-Se induce bandgap narrowing while Cl-Se broadens
the bandgap and reduces the electron carrier concentration. Our findings may assist in the development
of robust synthesis routes and the optimization of 2D
MoS 2 for energy, optoelectronics, and environmental
applications.
ACKNOWLEDGMENTS
The authors acknowledge ACEII-PTRE of Moi University for funding and CHPC-Cape Town for the
provision of High Performance Computing Resources
and support.
REFERENCES
[1] Wang, Q. H., Kalantar-Zadeh, K., Kis, A., Coleman, J.
N., & Strano, M. S. (2012). Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nature nanotechnology, 7(11), 699–712.
[2] Lalmi, B., Oughaddou, H., Enriquez, H., Kara, A.,
Vizzini, S., Ealet, B., & Aufray, B. (2010). Epitaxial
growth of a silicene sheet. Applied Physics Letters,
97(22), 223109.
[3] Geim, A. K., & Novoselov, K. S. (2010). The rise of
graphene. In Nanoscience and technology: a collection
of reviews from nature journals (pp. 11–19).
[4] Korir, K. K., & Philemon, K. T. (2020). Tailoring
Single Walled Carbon Nanotube for Improved CO2
Gas Applications: Insights from Ab initio Simulations.
Materialia, 100694.
[5] Philemon, K. T., & Korir, K. K. (2020). Carbon dioxide
gas sensing, capture, and storage potential of calcium oxide surface and single walled carbon nanotube:
insights from ab initio simulation. Journal of Physics:
Condensed Matter, 32(24), 245901.
[6] Krasnozhon, D., Lembke, D., Nyffeler, C., Leblebici,
Y., & Kis, A. (2014). MoS2 transistors operating at
gigahertz frequencies. Nano letters, 14(10), 5905-5911.
[7] Liao, J., Sa, B., Zhou, J., Ahuja, R., & Sun, Z. (2014).
Design of high-efficiency visible-light photocatalysts
for water splitting:MoS 2 /AlN(GaN) heterostructures.
The Journal of Physical Chemistry C118(31), 17594–
17599.
[8] Lopez-Sanchez, O., Lembke, D., Kayci, M., Radenovic, A., & Kis, A. (2013). Ultrasensitive photodetectors
based on monolayer MoS 2 . Nature nanotechnology,
8(7), 497–501.
[9] Kaasbjerg, K., Thygesen, K. S., & Jacobsen, K. W.
(2012). Phonon-limited mobility in n-type single-layer
MoS 2 from first principles. Physical Review B, 85(11),
115317.
[10] Lee, H. S., Min, S. W., Chang, Y. G., Park, M. K., Nam,
T., Kim, H., & Im, S. (2012). MoS 2 nanosheet phototransistors with thickness-modulated optical energy
gap. Nano letters, 12(7), 3695–3700.
[11] Wang, H., Yu, L., Lee, Y. H., Shi, Y., Hsu, A., Chin,
M. L., & Palacios, T. (2012). Integrated circuits based
on bilayer MoS2 transistors. Nano letters, 12(9), 4674–
4680.
[12] Mak, K. F., Lee, C., Hone, J., Shan, J., & Heinz,
T. F. (2010). Atomically thin MoS 2 : a new directgap semiconductor. Physical review letters 105(13),
136805.
[13] Scalise, E., Houssa, M., Pourtois, G., Afanas’ev, V.,
& Stesmans, A. (2012). Strain-induced semiconductor
to metal transition in the two-dimensional honeycomb
structure of MoS 2 . Nano Research, 5(1), 43–48.
[14] Ramasubramaniam, A., Naveh, D., & Towe, E. (2011).
Tunable bandgaps in bilayer transition-metal dichalcogenides. Physical Review B, 84(20), 205325.
[15] Ma, Y., Dai, Y., Guo, M., Niu, C., Lu, J., & Huang, B.
(2011). Electronic and magnetic properties of perfect,
vacancy-doped, and nonmetal adsorbed MoSe 2 , MoTe 2
and WS 2 monolayers. Physical Chemistry Chemical
Physics, 13(34), 15546–15553.
[16] McDonnell, S., Addou, R., Buie, C., Wallace, R. M.,
& Hinkle, C. L. (2014). Defect-dominated doping and
contact resistance in MoS 2 ACS nano, 8(3), 2880–2888.
[17] Gao, J., Kim,Y. D., Liang, L., Idrobo, J. C., Chow, P.,Tan,
J., & Koratkar, N. (2016). Transition-metal substitution
doping in synthetic atomically thin semiconductors.
Advanced Materials 28(44), 9735–9743.
[18] Fu, Y., Long, M., Gao, A., Wang, Y., Pan, C., Liu,
X., & Miao, F. (2017). Intrinsic p-type W-based
transition metal dichalcogenide by substitutional Tadoping.Applied Physics Letters 111(4), 043502.
[19] Kohn, W., & Sham, L. J. (1965). Self-consistent equations including exchange and correlation effects. Physical review 140(4A), A1133.
[20] Giannozzi, P., Baroni, S., Bonini, N., Calandra, M.,
Car, R., Cavazzoni, C., & Wentzcovitch, R. M. (2009).
QUANTUM ESPRESSO: a modular and open-source
software project for quantum simulations of materials.
Journal of physics: Condensed matter, 21(39), 395502.
[21] Ernzerhof, M., & Scuseria, G. E. (1999). Assessment
of the Perdew–Burke–Ernzerhof exchange-correlation
functional. The Journal of chemical physics, 110(11),
5029–5036.
[22] Vanderbilt, D. (1990). Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Physical
review B41(11), 7892.
[23] Monkhorst, H. J., & Pack, J. D. (1976). Special points for
Brillouin-zone integrations. Physical review B13(12),
5188.
[24] Ataca, C., Sahin, H., Akturk, E., & Ciraci, S. (2011).
Mechanical and electronic properties of MoS2 nanoribbons and their defects. The Journal of Physical Chemistry C115(10), 3934–3941.
[25] Nolan, M. (2011). Charge compensation and Ce3+ formation in trivalent doping of the CeO2 (110) surface: the
key role of dopant ionic radius. The Journal of Physical
Chemistry C115(14), 6671–6681.
161
may guide synthesis and utilization in various areas. It
is found that the dopants considered in this study can
be achieved under non-equilibrium conditions with O
and P having the lowest and highest formation energy,
respectively. It is noted that O and Cl dopants induce
bandgap narrowing and at higher concentration the
system becomes insensitive to O, while it responds
to Cl up to 31%.
On the other hand, P and Se dopants induce bandgap
broadening of 2D MoS 2 and at a higher concentration above 31% the system becomes insensitive. It
was further observed that co-dopants Cl-P, O-P, and
O-Se induce bandgap narrowing while Cl-Se broadens
the bandgap and reduces the electron carrier concentration. Our findings may assist in the development
of robust synthesis routes and the optimization of 2D
MoS 2 for energy, optoelectronics, and environmental
applications.
ACKNOWLEDGMENTS
The authors acknowledge ACEII-PTRE of Moi University for funding and CHPC-Cape Town for the
provision of High Performance Computing Resources
and support.
REFERENCES
[1] Wang, Q. H., Kalantar-Zadeh, K., Kis, A., Coleman, J.
N., & Strano, M. S. (2012). Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nature nanotechnology, 7(11), 699–712.
[2] Lalmi, B., Oughaddou, H., Enriquez, H., Kara, A.,
Vizzini, S., Ealet, B., & Aufray, B. (2010). Epitaxial
growth of a silicene sheet. Applied Physics Letters,
97(22), 223109.
[3] Geim, A. K., & Novoselov, K. S. (2010). The rise of
graphene. In Nanoscience and technology: a collection
of reviews from nature journals (pp. 11–19).
[4] Korir, K. K., & Philemon, K. T. (2020). Tailoring
Single Walled Carbon Nanotube for Improved CO2
Gas Applications: Insights from Ab initio Simulations.
Materialia, 100694.
[5] Philemon, K. T., & Korir, K. K. (2020). Carbon dioxide
gas sensing, capture, and storage potential of calcium oxide surface and single walled carbon nanotube:
insights from ab initio simulation. Journal of Physics:
Condensed Matter, 32(24), 245901.
[6] Krasnozhon, D., Lembke, D., Nyffeler, C., Leblebici,
Y., & Kis, A. (2014). MoS2 transistors operating at
gigahertz frequencies. Nano letters, 14(10), 5905-5911.
[7] Liao, J., Sa, B., Zhou, J., Ahuja, R., & Sun, Z. (2014).
Design of high-efficiency visible-light photocatalysts
for water splitting:MoS 2 /AlN(GaN) heterostructures.
The Journal of Physical Chemistry C118(31), 17594–
17599.
[8] Lopez-Sanchez, O., Lembke, D., Kayci, M., Radenovic, A., & Kis, A. (2013). Ultrasensitive photodetectors
based on monolayer MoS 2 . Nature nanotechnology,
8(7), 497–501.
[9] Kaasbjerg, K., Thygesen, K. S., & Jacobsen, K. W.
(2012). Phonon-limited mobility in n-type single-layer
MoS 2 from first principles. Physical Review B, 85(11),
115317.
[10] Lee, H. S., Min, S. W., Chang, Y. G., Park, M. K., Nam,
T., Kim, H., & Im, S. (2012). MoS 2 nanosheet phototransistors with thickness-modulated optical energy
gap. Nano letters, 12(7), 3695–3700.
[11] Wang, H., Yu, L., Lee, Y. H., Shi, Y., Hsu, A., Chin,
M. L., & Palacios, T. (2012). Integrated circuits based
on bilayer MoS2 transistors. Nano letters, 12(9), 4674–
4680.
[12] Mak, K. F., Lee, C., Hone, J., Shan, J., & Heinz,
T. F. (2010). Atomically thin MoS 2 : a new directgap semiconductor. Physical review letters 105(13),
136805.
[13] Scalise, E., Houssa, M., Pourtois, G., Afanas’ev, V.,
& Stesmans, A. (2012). Strain-induced semiconductor
to metal transition in the two-dimensional honeycomb
structure of MoS 2 . Nano Research, 5(1), 43–48.
[14] Ramasubramaniam, A., Naveh, D., & Towe, E. (2011).
Tunable bandgaps in bilayer transition-metal dichalcogenides. Physical Review B, 84(20), 205325.
[15] Ma, Y., Dai, Y., Guo, M., Niu, C., Lu, J., & Huang, B.
(2011). Electronic and magnetic properties of perfect,
vacancy-doped, and nonmetal adsorbed MoSe 2 , MoTe 2
and WS 2 monolayers. Physical Chemistry Chemical
Physics, 13(34), 15546–15553.
[16] McDonnell, S., Addou, R., Buie, C., Wallace, R. M.,
& Hinkle, C. L. (2014). Defect-dominated doping and
contact resistance in MoS 2 ACS nano, 8(3), 2880–2888.
[17] Gao, J., Kim,Y. D., Liang, L., Idrobo, J. C., Chow, P.,Tan,
J., & Koratkar, N. (2016). Transition-metal substitution
doping in synthetic atomically thin semiconductors.
Advanced Materials 28(44), 9735–9743.
[18] Fu, Y., Long, M., Gao, A., Wang, Y., Pan, C., Liu,
X., & Miao, F. (2017). Intrinsic p-type W-based
transition metal dichalcogenide by substitutional Tadoping.Applied Physics Letters 111(4), 043502.
[19] Kohn, W., & Sham, L. J. (1965). Self-consistent equations including exchange and correlation effects. Physical review 140(4A), A1133.
[20] Giannozzi, P., Baroni, S., Bonini, N., Calandra, M.,
Car, R., Cavazzoni, C., & Wentzcovitch, R. M. (2009).
QUANTUM ESPRESSO: a modular and open-source
software project for quantum simulations of materials.
Journal of physics: Condensed matter, 21(39), 395502.
[21] Ernzerhof, M., & Scuseria, G. E. (1999). Assessment
of the Perdew–Burke–Ernzerhof exchange-correlation
functional. The Journal of chemical physics, 110(11),
5029–5036.
[22] Vanderbilt, D. (1990). Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Physical
review B41(11), 7892.
[23] Monkhorst, H. J., & Pack, J. D. (1976). Special points for
Brillouin-zone integrations. Physical review B13(12),
5188.
[24] Ataca, C., Sahin, H., Akturk, E., & Ciraci, S. (2011).
Mechanical and electronic properties of MoS2 nanoribbons and their defects. The Journal of Physical Chemistry C115(10), 3934–3941.
[25] Nolan, M. (2011). Charge compensation and Ce3+ formation in trivalent doping of the CeO2 (110) surface: the
key role of dopant ionic radius. The Journal of Physical
Chemistry C115(14), 6671–6681.
161