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Patterned arrays of lateral heterojunctions within monolayer two-dimensional semiconductors.

Mahjouri-Samani M, Lin MW, Wang K, Lupini AR, Lee J, Basile L, Boulesbaa A, Rouleau CM, Puretzky AA, Ivanov IN, Xiao K, Yoon M, Geohegan DB - Nat Commun (2015)

Bottom Line: The formation of semiconductor heterojunctions and their high-density integration are foundations of modern electronics and optoelectronics.Electron beam lithography is used to pattern MoSe2 monolayer crystals with SiO2, and the exposed locations are selectively and totally converted to MoS2 using pulsed laser vaporization of sulfur to form MoSe2/MoS2 heterojunctions in predefined patterns.This demonstration of lateral heterojunction arrays within a monolayer crystal is an essential step for the integration of two-dimensional semiconductor building blocks with different electronic and optoelectronic properties for high-density, ultrathin devices.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.

ABSTRACT
The formation of semiconductor heterojunctions and their high-density integration are foundations of modern electronics and optoelectronics. To enable two-dimensional crystalline semiconductors as building blocks in next-generation electronics, developing methods to deterministically form lateral heterojunctions is crucial. Here we demonstrate an approach for the formation of lithographically patterned arrays of lateral semiconducting heterojunctions within a single two-dimensional crystal. Electron beam lithography is used to pattern MoSe2 monolayer crystals with SiO2, and the exposed locations are selectively and totally converted to MoS2 using pulsed laser vaporization of sulfur to form MoSe2/MoS2 heterojunctions in predefined patterns. The junctions and conversion process are studied by Raman and photoluminescence spectroscopy, atomically resolved scanning transmission electron microscopy and device characterization. This demonstration of lateral heterojunction arrays within a monolayer crystal is an essential step for the integration of two-dimensional semiconductor building blocks with different electronic and optoelectronic properties for high-density, ultrathin devices.

No MeSH data available.


Schematic illustration of the experimental steps for the formation of MoSe2/MoS2 heterojunction arrays.(a) Starting MoSe2 monolayer crystal. (b) MoSe2 is patterned by e-beam lithography and SiO2 deposition, followed by sulfurization of uncovered areas. The SiO2 mask is used to prevent the underlying MoSe2 regions from reacting with sulfur while the exposed regions are converted to MoS2. (c) Formation of arrays of lateral MoSe2/MoS2 heterojunctions within the monolayer crystal.
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f1: Schematic illustration of the experimental steps for the formation of MoSe2/MoS2 heterojunction arrays.(a) Starting MoSe2 monolayer crystal. (b) MoSe2 is patterned by e-beam lithography and SiO2 deposition, followed by sulfurization of uncovered areas. The SiO2 mask is used to prevent the underlying MoSe2 regions from reacting with sulfur while the exposed regions are converted to MoS2. (c) Formation of arrays of lateral MoSe2/MoS2 heterojunctions within the monolayer crystal.

Mentions: Figure 1 schematically illustrates the experimental steps for the formation of periodic lateral heterojunctions. The starting monolayer MoSe2 crystals with lateral sizes ranging from 10 to 100 μm were synthesized using a previously reported method1113 (Supplementary Fig. 1; Supplementary Note 1). The crystals were then simply masked by conventional patterning processes, followed by selective conversion of the unmasked MoSe2 to MoS2 by pulsed laser vaporization of sulfur. The masking material (∼50 nm SiO2) was electron beam evaporated and was found to be quite effective in protecting the areas of the 2D crystal underneath from sulfurization.


Patterned arrays of lateral heterojunctions within monolayer two-dimensional semiconductors.

Mahjouri-Samani M, Lin MW, Wang K, Lupini AR, Lee J, Basile L, Boulesbaa A, Rouleau CM, Puretzky AA, Ivanov IN, Xiao K, Yoon M, Geohegan DB - Nat Commun (2015)

Schematic illustration of the experimental steps for the formation of MoSe2/MoS2 heterojunction arrays.(a) Starting MoSe2 monolayer crystal. (b) MoSe2 is patterned by e-beam lithography and SiO2 deposition, followed by sulfurization of uncovered areas. The SiO2 mask is used to prevent the underlying MoSe2 regions from reacting with sulfur while the exposed regions are converted to MoS2. (c) Formation of arrays of lateral MoSe2/MoS2 heterojunctions within the monolayer crystal.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525195&req=5

f1: Schematic illustration of the experimental steps for the formation of MoSe2/MoS2 heterojunction arrays.(a) Starting MoSe2 monolayer crystal. (b) MoSe2 is patterned by e-beam lithography and SiO2 deposition, followed by sulfurization of uncovered areas. The SiO2 mask is used to prevent the underlying MoSe2 regions from reacting with sulfur while the exposed regions are converted to MoS2. (c) Formation of arrays of lateral MoSe2/MoS2 heterojunctions within the monolayer crystal.
Mentions: Figure 1 schematically illustrates the experimental steps for the formation of periodic lateral heterojunctions. The starting monolayer MoSe2 crystals with lateral sizes ranging from 10 to 100 μm were synthesized using a previously reported method1113 (Supplementary Fig. 1; Supplementary Note 1). The crystals were then simply masked by conventional patterning processes, followed by selective conversion of the unmasked MoSe2 to MoS2 by pulsed laser vaporization of sulfur. The masking material (∼50 nm SiO2) was electron beam evaporated and was found to be quite effective in protecting the areas of the 2D crystal underneath from sulfurization.

Bottom Line: The formation of semiconductor heterojunctions and their high-density integration are foundations of modern electronics and optoelectronics.Electron beam lithography is used to pattern MoSe2 monolayer crystals with SiO2, and the exposed locations are selectively and totally converted to MoS2 using pulsed laser vaporization of sulfur to form MoSe2/MoS2 heterojunctions in predefined patterns.This demonstration of lateral heterojunction arrays within a monolayer crystal is an essential step for the integration of two-dimensional semiconductor building blocks with different electronic and optoelectronic properties for high-density, ultrathin devices.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.

ABSTRACT
The formation of semiconductor heterojunctions and their high-density integration are foundations of modern electronics and optoelectronics. To enable two-dimensional crystalline semiconductors as building blocks in next-generation electronics, developing methods to deterministically form lateral heterojunctions is crucial. Here we demonstrate an approach for the formation of lithographically patterned arrays of lateral semiconducting heterojunctions within a single two-dimensional crystal. Electron beam lithography is used to pattern MoSe2 monolayer crystals with SiO2, and the exposed locations are selectively and totally converted to MoS2 using pulsed laser vaporization of sulfur to form MoSe2/MoS2 heterojunctions in predefined patterns. The junctions and conversion process are studied by Raman and photoluminescence spectroscopy, atomically resolved scanning transmission electron microscopy and device characterization. This demonstration of lateral heterojunction arrays within a monolayer crystal is an essential step for the integration of two-dimensional semiconductor building blocks with different electronic and optoelectronic properties for high-density, ultrathin devices.

No MeSH data available.