Tuning the electronic structure of monolayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Mo</mml:mi><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> towards metal like via vanadium doping

Abstract

Doping of two-dimensional layered semiconducting materials is becoming pivotal in tailoring their electronic properties, enabling the development of advanced electronic and optoelectronic devices, where the selection of dopant is important. Here, we demonstrate the potential of substitutional vanadium (V) doping in monolayer molybdenum disulfide (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>Mo</a:mi><a:msub><a:mi mathvariant="normal">S</a:mi><a:mn>2</a:mn></a:msub></a:mrow></a:math>) lattice in different extents leading to tunable electronic and optoelectronic properties. We found that low-level V doping (∼1 <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mtext>at.</c:mtext><c:mspace width="0.16em"/><c:mo>%</c:mo></c:mrow></c:math>) induces <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mi>p</e:mi></e:math>-type characteristics in otherwise <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mi>n</f:mi></f:math>-type monolayer <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mrow><g:mi>Mo</g:mi><g:msub><g:mi mathvariant="normal">S</g:mi><g:mn>2</g:mn></g:msub></g:mrow></g:math>, whereas medium-level doping (∼5 <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:mrow><i:mtext>at.</i:mtext><i:mspace width="0.16em"/><i:mo>%</i:mo></i:mrow></i:math>) leads to an ambipolar semiconductor. Degenerately doped <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mrow><k:mi>Mo</k:mi><k:msub><k:mi mathvariant="normal">S</k:mi><k:mn>2</k:mn></k:msub></k:mrow></k:math> (∼9 <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mrow><m:mtext>at.</m:mtext><m:mspace width="0.16em"/><m:mo>%</m:mo></m:mrow></m:math>) facilitates a transition from semiconducting towards metallic (metal-like) with reduced electrical resistivity (∼4.5 <o:math xmlns:o="http://www.w3.org/1998/Math/MathML"><o:mrow><o:mi mathvariant="normal">Ω</o:mi><o:mspace width="0.16em"/><o:mtext>m</o:mtext></o:mrow></o:math> of <r:math xmlns:r="http://www.w3.org/1998/Math/MathML"><r:mrow><r:mi>Mo</r:mi><r:msub><r:mi mathvariant="normal">S</r:mi><r:mn>2</r:mn></r:msub></r:mrow></r:math> to <t:math xmlns:t="http://www.w3.org/1998/Math/MathML"><t:mrow><t:mo>∼</t:mo><t:mn>2.2</t:mn><t:mo>×</t:mo><t:msup><t:mrow><t:mn>10</t:mn></t:mrow><t:mrow><t:mo>−</t:mo><t:mn>5</t:mn></t:mrow></t:msup><t:mi mathvariant="normal">Ω</t:mi><t:mspace width="0.16em"/><t:mtext>m</t:mtext></t:mrow></t:math>), low activation energy for transport (∼11 meV), and electric field independent drain current in field effect transistor–based transfer characteristics. A detailed temperature- and power-dependent photoluminescence study along with density functional theory–based calculations in support unravels the emergence of an excitonic transition at ∼850 nm with its intensity dependent on the amount of vanadium. This study shows the potential of V doping in <w:math xmlns:w="http://www.w3.org/1998/Math/MathML"><w:mrow><w:mi>Mo</w:mi><w:msub><w:mi mathvariant="normal">S</w:mi><w:mn>2</w:mn></w:msub></w:mrow></w:math> for generating multifunctional two-dimensional materials for next generation electronics, optoelectronics, and interconnects with systematic control over its electronic structure in a wide range. Published by the American Physical Society 2024

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