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Alvarosinde (talk | contribs) m Correction of typographical errors: diffucult, dimensinol, passion ratio (Poisson’s ratio) |
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[[Phosphorene]] is a 2-dimensional, crystalline allotrope of [[phosphorus]]. Its mono-atomic hexagonal structure makes it conceptually similar to graphene. However, phosphorene has substantially different electronic properties; in particular it possesses a nonzero band gap while displaying high electron mobility.<ref name=":0">{{Cite web|title = Beyond Graphene, a Zoo of New 2-D Materials|url = http://blogs.discovermagazine.com/crux/2015/07/17/beyond-graphene/#.Vane-PlVhBe |publisher=Discover Magazine |first=Andy |last=Berger |date= July 17, 2015 |access-date = 2015-09-19}}</ref> This property potentially makes it a better semiconductor than graphene.<ref>{{Cite journal | doi = 10.1038/nnano.2014.35| title = Black phosphorus field-effect transistors| journal = Nature Nanotechnology| volume = 9| issue = 5| pages = 372–377| year = 2014| last1 = Li | first1 = L. | last2 = Yu | first2 = Y. | last3 = Ye | first3 = G. J. | last4 = Ge | first4 = Q. | last5 = Ou | first5 = X. | last6 = Wu | first6 = H. | last7 = Feng | first7 = D. | last8 = Chen | first8 = X. H. | last9 = Zhang | first9 = Y.
|arxiv = 1401.4117 |bibcode = 2014NatNa...9..372L | pmid=24584274| s2cid = 17218693}}</ref>
The synthesis of phosphorene mainly consists of micromechanical cleavage or liquid phase exfoliation methods. The former has a low yield while the latter produce free standing nanosheets in solvent and not on the solid support. The bottom-up approaches like chemical vapor deposition (CVD) are still blank because of its high reactivity. Therefore, in the current scenario, the most effective method for large area fabrication of thin films of phosphorene consists of wet assembly techniques like [[Langmuir–Blodgett film|Langmuir-Blodgett]] involving the assembly followed by deposition of nanosheets on solid supports.<ref name="ReferenceA">{{Cite journal | doi = 10.1038/srep34095 | pmid = 27671093| pmc = 5037434| title = Large Area Fabrication of Semiconducting Phosphorene by Langmuir-Blodgett Assembly| journal = Sci. Rep.| volume = 6| pages = 34095| year = 2016| last1 = Ritu | first1 = Harneet | bibcode = 2016NatSR...634095K| arxiv = 1605.00875}}</ref>
=== Sb: antimonene ===
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=== Bi: bismuthene ===
Bismuthene, the two-dimensional (2D) allotrope of [[bismuth]], was predicted to be a topological insulator. It was predicted that bismuthene retains its topological phase when grown on [[silicon carbide]] in 2015.<ref>{{Cite journal|last1=Hsu|first1=Chia-Hsiu|last2=Huang|first2=Zhi-Quan|last3=Chuang|first3=Feng-Chuan|last4=Kuo|first4=Chien-Cheng|last5=Liu|first5=Yu-Tzu|last6=Lin|first6=Hsin|last7=Bansil|first7=Arun|date=2015-02-10|title=The nontrivial electronic structure of Bi/Sb honeycombs on SiC(0001)|journal=New Journal of Physics|volume=17|issue=2|pages=025005|doi=10.1088/1367-2630/17/2/025005|bibcode=2015NJPh...17b5005H|doi-access=free}}</ref> The prediction was successfully realized and synthesized in 2016.<ref>{{Cite journal|title = Bismuthene on a SiC substrate: A candidate for a high-temperature quantum spin Hall material|date = July 21, 2017|journal = Science|doi = 10.1126/science.aai8142 |pmid =28663438|volume=357|issue = 6348|pages=287–290|bibcode =2017Sci...357..287R | last1 = Reis | first1 = Felix | last2 = Li| first2 = Gang | last3 = Dudy | first3 = Lenart | last4 = Bauernfiend | first4 = Maximilian | last5 = Glass | first5 = Stefan | last6 = Hanke | first6 = Werner | last7 = Thomale | first7 = Ronny | last8 = Schaefer | first8 = Joerg | last9 = Claessen | first9 = Ralph|arxiv = 1608.00812|s2cid = 23323210}}</ref> At first glance the system is similar to graphene, as the Bi atoms arrange in a honeycomb lattice. However the [[bandgap]] is as large as 800mV due to the large [[
=== Metals ===
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== Combined surface alloying ==
Often single-layer materials, specifically elemental allotrops, are connected to the supporting substrate via surface alloys.<ref name=alloy/><ref name="Yuhara etal"/> By now, this phenomena has been proven via a combination of different measurement techniques for silicene,<ref name=alloy/> for which the alloy is
== Organic ==
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Microscopy techniques such as [[transmission electron microscopy]],<ref name=":19">{{Cite journal|last1=Butler|first1=Sheneve Z.|last2=Hollen|first2=Shawna M.|last3=Cao|first3=Linyou|last4=Cui|first4=Yi|last5=Gupta|first5=Jay A.|last6=Gutiérrez|first6=Humberto R.|last7=Heinz|first7=Tony F.|last8=Hong|first8=Seung Sae|last9=Huang|first9=Jiaxing|title=Progress, Challenges, and Opportunities in Two-Dimensional Materials Beyond Graphene|journal=ACS Nano|volume=7|issue=4|pages=2898–2926|doi=10.1021/nn400280c|pmid=23464873|year=2013}}</ref><ref name="Bhimanapati 11509–11539">{{Cite journal|last1=Bhimanapati|first1=Ganesh R.|last2=Lin|first2=Zhong|last3=Meunier|first3=Vincent|last4=Jung|first4=Yeonwoong|last5=Cha|first5=Judy|last6=Das|first6=Saptarshi|last7=Xiao|first7=Di|last8=Son|first8=Youngwoo|author-link9=Michael Strano|last9=Strano|first9=Michael S.|title=Recent Advances in Two-Dimensional Materials beyond Graphene|journal=ACS Nano|volume=9|issue=12|pages=11509–11539|doi=10.1021/acsnano.5b05556|pmid=26544756|year=2015}}</ref><ref name=":20">{{Cite journal|last1=Rao|first1=C. N. R.|last2=Nag|first2=Angshuman|date=2010-09-01|title=Inorganic Analogues of Graphene|journal=European Journal of Inorganic Chemistry|volume=2010|issue=27|pages=4244–4250|doi=10.1002/ejic.201000408}}</ref> 3D [[electron diffraction]],<ref name="hovden2019">{{Cite journal|last1=Sung|first1=S.H.|last2=Schnitzer|first2=N.|last3=Brown|first3=L.|last4=Park|first4=J.|last5=Hovden|first5=R.|date=2019-06-25|title=Stacking, strain, and twist in 2D materials quantified by 3D electron diffraction|journal=Physical Review Materials|volume=3|issue=6|pages=064003|doi=10.1103/PhysRevMaterials.3.064003|bibcode=2019PhRvM...3f4003S|arxiv=1905.11354|s2cid=166228311}}</ref> [[scanning probe microscopy]],<ref name=":54">{{Cite journal|last1=Rao|first1=C. N. R.|last2=Ramakrishna Matte|first2=H. S. S.|last3=Maitra|first3=Urmimala|date=2013-12-09|title=Graphene Analogues of Inorganic Layered Materials|journal=Angewandte Chemie International Edition|volume=52|issue=50|pages=13162–13185|doi=10.1002/anie.201301548|pmid=24127325}}</ref> [[scanning tunneling microscope]],<ref name=":19" /> and [[atomic-force microscopy]]<ref name=":19" /><ref name=":20" /><ref name=":54" /> are used to characterize the thickness and size of the 2D materials. Electrical properties and structural properties such as composition and defects are characterized by [[Raman spectroscopy]],<ref name=":19" /><ref name=":20" /><ref name=":54" /> [[X-ray crystallography|X-ray diffraction]],<ref name=":19" /><ref name=":20" /> and [[X-ray photoelectron spectroscopy]].<ref name=":133">{{Cite journal|date=2015-01-01|title=Inorganic Graphene Analogs|journal=[[Annual Review of Materials Research]]|volume=45|issue=1|pages=29–62|doi=10.1146/annurev-matsci-070214-021141|bibcode=2015AnRMS..45...29R|last1=Rao|first1=C. N. R|last2=Maitra|first2=Urmimala}}</ref>
=== Mechanical
The mechanical characterization of 2D materials is difficult due to ambient reactivity and substrate constraints present in many 2D materials. To this end, many mechanical properties are calculated using [[molecular dynamics]] simulations or [[molecular mechanics]] simulations. Experimental mechanical characterization is possible in 2D materials which can survive the conditions of the experimental setup as well as can be deposited on suitable substrates or exist in a free-standing form. Many 2D materials also possess out-of-plane deformation which further convolute measurements.<ref>{{Cite journal |last1=Androulidakis |first1=Charalampos |last2=Zhang |first2=Kaihao |last3=Robertson |first3=Matthew |last4=Tawfick |first4=Sameh |date=2018-06-13 |title=Tailoring the mechanical properties of 2D materials and heterostructures |url=https://iopscience.iop.org/article/10.1088/2053-1583/aac764 |journal=2D Materials |volume=5 |issue=3 |pages=032005 |doi=10.1088/2053-1583/aac764 |bibcode=2018TDM.....5c2005A |s2cid=139728037 |issn=2053-1583}}</ref>
[[Nanoindentation]] testing is commonly used to experimentally measure [[elastic modulus]], [[hardness]], and [[Fracture|fracture strength]] of 2D materials. From these directly measured values, models exist which allow the estimation of [[fracture toughness]], [[Work hardening|work hardening exponent]], residual stress, and [[Yield (engineering)|yield strength]]. These experiments are ran using dedicated nanoindentation equipment or an [[Atomic force microscopy|Atomic Force Microscope]] (AFM). Nanoindentation experiments are generally ran with the 2D material as a linear strip clamped on both ends experiencing indentation by a wedge, or with the 2D material as a circular membrane clamped around the circumference experiencing indentation by a curbed tip in the center. The strip geometry is difficult to prepare but allows for easier analysis due to linear resulting stress fields. The circular drum-like geometry is more commonly used and can be easily prepared by exfoliating samples onto a patterned substrate. The stress applied to the film in the clamping process can be is refereed to as the residual stress. In the case of very thin layers of 2D materials bending stress is generally ignored in indentation measurements, with bending stress becoming relevant in multilayer samples. Elastic modulus and residual stress values can be extracted by determining the linear and cubic portions of the experimental force-displacement curve. The fracture stress of the 2D sheet is extracted from the applied stress at failure of the sample. AFM tip size was found to have little effect on elastic property measurement, but the breaking force was found to have a strong tip size dependence due stress concentration at the apex of the tip.<ref name="auto">{{Cite journal |last1=Lee |first1=Changgu |last2=Wei |first2=Xiaoding |last3=Kysar |first3=Jeffrey W. |last4=Hone |first4=James |date=2008-07-18 |title=Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene |url=https://www.science.org/doi/10.1126/science.1157996 |journal=Science |language=en |volume=321 |issue=5887 |pages=385–388 |doi=10.1126/science.1157996 |pmid=18635798 |bibcode=2008Sci...321..385L |s2cid=206512830 |issn=0036-8075}}</ref> Using these techniques the elastic modulus and yield strength of graphene were found to be 342 N/m and 55 N/m respectively.<ref name="auto"/>
[[Poisson's ratio|Poisson’s ratio]] measurements in 2D materials is generally straightforward. To get a value, a 2D sheet is placed under stress and displacement responses are measured, or an MD calculation is ran. The unique structures found in 2D materials have been found to result in [[Auxetics|auxetic]] behavior in phosphorene<ref>{{Cite journal |last1=Jiang |first1=Jin-Wu |last2=Park |first2=Harold S. |date=2014-08-18 |title=Negative poisson's ratio in single-layer black phosphorus |url=https://www.nature.com/articles/ncomms5727 |journal=Nature Communications |language=en |volume=5 |issue=1 |pages=4727 |doi=10.1038/ncomms5727 |pmid=25131569 |arxiv=1403.4326 |bibcode=2014NatCo...5.4727J |s2cid=9132961 |issn=2041-1723}}</ref> and graphene<ref>{{Cite journal |last1=Jiang |first1=Jin-Wu |last2=Chang |first2=Tienchong |last3=Guo |first3=Xingming |last4=Park |first4=Harold S. |date=2016-08-10 |title=Intrinsic Negative Poisson's Ratio for Single-Layer Graphene |url=https://pubs.acs.org/doi/10.1021/acs.nanolett.6b02538 |journal=Nano Letters |language=en |volume=16 |issue=8 |pages=5286–5290 |doi=10.1021/acs.nanolett.6b02538 |pmid=27408994 |arxiv=1605.01827 |bibcode=2016NanoL..16.5286J |s2cid=33516006 |issn=1530-6984}}</ref> and a
[[Shear modulus]] measurements of graphene has been extracted by measuring a resonance frequency shift in a double paddle oscillator experiment as well as with MD simulations.<ref>{{Cite journal |last1=Liu |first1=Xiao |last2=Metcalf |first2=Thomas H. |last3=Robinson |first3=Jeremy T. |last4=Houston |first4=Brian H. |last5=Scarpa |first5=Fabrizio |date=2012-02-08 |title=Shear Modulus of Monolayer Graphene Prepared by Chemical Vapor Deposition |url=https://pubs.acs.org/doi/10.1021/nl204196v |journal=Nano Letters |language=en |volume=12 |issue=2 |pages=1013–1017 |doi=10.1021/nl204196v |pmid=22214257 |bibcode=2012NanoL..12.1013L |issn=1530-6984}}</ref><ref>{{Cite journal |last1=Min |first1=K. |last2=Aluru |first2=N. R. |date=2011-01-03 |title=Mechanical properties of graphene under shear deformation |url=http://aip.scitation.org/doi/10.1063/1.3534787 |journal=Applied Physics Letters |language=en |volume=98 |issue=1 |pages=013113 |doi=10.1063/1.3534787 |bibcode=2011ApPhL..98a3113M |issn=0003-6951}}</ref>
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