– English Lyrics

Lyrics & Translation

[English]

Two-dimensional materials are

crystalline substances with a thickness

of a few atoms or less.

The most famous of the 2D materials is graphene.

A single layer of carbon atoms called a monolayer,

which is hundreds of times stronger than steel,

conducts electricity better than copper,

and is completely flexible.

Beyond graphene there exists a host of 2D materials

with a wide range of different properties.

One group called transition metal dichalcogenides,

and known as TMDs,

combine the incredible thinness of graphene

with exceptional semiconductor properties.

Unlike graphene, a TMD monolayer is three atoms thick.

Each sheet consists of a layer of transition metal atoms,

such as molybdenum

or tungsten,

between two planes of chalcogen atoms,

such as sulfur

or selenium.

TMD monolayers are direct bandgap semiconductors,

meaning they strongly emit light

when excited electrically or optically.

But for thicker TMD sheets such as bilayers

and trilayers

the bandgap is indirect and

the excellent luminescence properties are lost.

So, to utilise light emission from TMDs

individual monolayers must be isolated from a bulk crystal.

To do this researchers at the University of Sheffield

use a method known as mechanical exfoliation.

Although atoms within an individual layer

are strongly bonded to one another,

adjacent sheets are bound together very weakly

through the van der Waals interaction.

By simply applying sticky tape to the crystal

this weak interlayer bonding can be broken

and thin films of material

can be removed from the crystal surface.

By then applying this tape onto a substrate,

such as glass, and slowly peeling it back off

interlayer bonding between layers

within the thin films can be broken further

and single monolayers can be

transferred onto the surface.

Assembling different 2D materials into vertical stacks,

one layer at a time,

creates new artificial materials

called van der Waals heterostructures.

By careful control of the sheet order

within the heterostructure

the properties of each individual layer can be combined

to produce optoelectronic devices

with tailor-made properties.

This allows the construction of

electroluminescent devices

for light-emitting applications,

as well as photodetectors

for optical imaging sensors,

and 2D material transistors

for the basis of flexible computational elements.

Combining these different

electrical and optical elements

based upon van der Waals heterostructures

has incredible potential for

the development of new flexible

electronic devices that could

revolutionize current technology.

Key Grammar Structures

• Two-dimensional materials are crystalline substances with a thickness of a few atoms or less.

  ➔ Noun phrase with compound adjective (two-dimensional) + verb 'to be' + complement

  ➔ The phrase 'two-dimensional' functions as a compound adjective describing 'materials'.

• which is hundreds of times stronger than steel,

  ➔ Relative clause with comparison 'stronger than'

  ➔ The relative clause beginning with 'which' describes the noun 'monolayer', showing comparison in degree of strength.

• Beyond graphene there exists a host of 2D materials

  ➔ Inverted sentence for emphasis (verb before subject)

  ➔ The structure 'there exists' places the verb before the subject to emphasize existence.

• Each sheet consists of a layer of transition metal atoms,

  ➔ Verb phrase 'consists of' (phrasal verb expressing composition)

  ➔ The verb phrase 'consists of' means that something is made up of specific parts.

• TMD monolayers are direct bandgap semiconductors,

  ➔ Linking verb 'to be' connecting subject and complement (classification)

  ➔ 'are' links 'TMD monolayers' with their classification 'semiconductors'.

• By simply applying sticky tape to the crystal this weak interlayer bonding can be broken

  ➔ Passive voice with modal verb ('can be broken') and participial phrase ('By applying ...')

  ➔ The participial phrase 'By applying...' expresses the method, while 'can be broken' shows possibility in passive voice.

• Assembling different 2D materials into vertical stacks, one layer at a time, creates new artificial materials

  ➔ Gerund phrase as subject ('Assembling ... creates ...')

  ➔ The gerund 'Assembling' functions as the subject of the verb 'creates'.

• By careful control of the sheet order within the heterostructure the properties of each individual layer can be combined

  ➔ Passive voice with modal ('can be combined') + prepositional phrase ('By careful control ...')

  ➔ The structure 'can be combined' expresses possibility, and 'By careful control...' indicates the manner or means.

• This allows the construction of electroluminescent devices for light-emitting applications,

  ➔ Verb 'allow' + object + infinitive/noun phrase (causative use)

  ➔ The verb 'allows' introduces a causative meaning, showing that one thing makes another possible.

• has incredible potential for the development of new flexible electronic devices

  ➔ Noun phrase with 'has' (possession) + prepositional phrase ('for ...') expressing purpose

  ➔ 'has incredible potential' expresses possession of capability, while 'for the development...' defines purpose.