Negative differential resistance in new structures based on graphene nanoribbons

Sharifi, Mohammad Javad; Akhoundi, Elaheh; Esmaili, Hamed

doi:10.1007/s10825-016-0929-8

Cited by 14 publications

(8 citation statements)

References 42 publications

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“…Nonetheless, significant difficulty in synthesizing atomically precise, eptiaxial heterostructures has made it very challenging to realize such superlattice structures [2][3][4][5][6][7][8] . Much work has been done on modeling graphene nanoribbon heterostructures and superlattices which could exhibit NDR [9][10][11][12][13][14][15] . Other work has been done on steep slope devices based on GNR and CNT heterojunctions 16,17 .…”

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confidence: 99%

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

Smith

Llinas

Bokor

et al. 2018

IEEE Electron Device Lett.

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Ballistic quantum transport calculations based on the non-equilbrium Green's function formalism show that field-effect transistor devices made from chevron-type graphene nanoribbons (CGNRs) could exhibit negative differential resistance with peak-to-valley ratios in excess of 4800 at room temperature as well as steepslope switching with 6 mV/decade subtheshold swing over five orders of magnitude and ON-currents of 88 µA µm −1 . This is enabled by the superlattice-like structure of these ribbons that have large periodic unit cells with regions of different effective bandgap, resulting in minibands and gaps in the density of states above the conduction band edge. The CGNR ribbon used in our proposed device has been previously fabricated with bottom-up chemical synthesis techniques and could be incorporated into an experimentally-realizable structure.In 1970, L.Esaki and R. Tsu predicted 1 that in an appropriately made superlattice, it should be possible to obtain very narrow width bands, which could then lead to negative differential resistance. The remarkable property of these superlattices is in the fact that, unlike the Esaki diodes, this negative differential resistance does not need any tunneling, rather it comes from the direct conduction of electrons. Nonetheless, significant difficulty in synthesizing atomically precise, eptiaxial heterostructures has made it very challenging to realize such superlattice structures 2-8 . Much work has been done on modeling graphene nanoribbon heterostructures and superlattices which could exhibit NDR 9-15 . Other work has been done on steep slope devices based on GNR and CNT heterojunctions 16,17 . Gnani et al. showed how superlattices could be used in a III-V nanowire FET to achieve steep slope behavior by using the superlattice gap to filter high energy electrons in the OFF state 18 . Here, we show that the recently synthesized chevron nanoribbons 19 provides a natural, monolithic material system where narrow-width energy bands and negative differential resistance (NDR) can be achieved. Our atomistic calculations predict that the NDR behavior should manifest at room temperature along with sub-thermal steepness (<60 mV/decade at room temperature). Such NDR behavior could lead to completely novel devices for next generation electronics.Unlike a graphene sheet, a narrow strip etched out of graphene, often called a graphene nanoribbon (GNR), can provide a sizeable bandgap. As a result, GNRs could lead to devices with good ON/OFF ratio at the nanoscale. However, a number of studies have also shown the deleterious effect of edge roughness on the device performance 20,21 . Recent breakthroughs in bottom-up chemical synthesis can produce GNRs with atomistically pristine edge states and overcome this shortcoming 19 . In fact, a recent experimental work demonstrated working transistors with 9-and 13-AGNRs made with these techniques 22 . The methods used to synthesize these ribbons can also be used to generate complex periodic structures beyond simply armchair and zigzag nanoribbon...

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confidence: 99%

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

Smith

Llinas

Bokor

et al. 2018

IEEE Electron Device Lett.

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“…On the other hand, the valley current I v , which is dominated by thermal broadening and the thermionic emission currents, enhances exponentially with rise in temperature. Both these effects give rise to a decreasing trend in the PVR with the increase in temperature [26,38,40].…”

Section: Resultsmentioning

confidence: 99%

Performance enhancement of armchair graphene nanoribbon resonant tunneling diode using V-shaped potential well

Mishra¹,

Das²,

Sahoo³

et al. 2021

Phys. Scr.

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We study the electron transport in armchair graphene nanoribbon (AGNR) resonant tunneling diode (RTD) using square and V-shaped potential well profiles. We use non-equilibrium Green’s function formalism to analyze the transmission and I-V characteristics. Results show that an enhancement in the peak current (Ip ) can be obtained by reducing the well width (Ww ) or barrier width (Wb ). As Ww decreases, Ip shifts to a higher peak voltage (Vp ), while there is almost no change in Vp with decreasing Wb . It is gratifying to note that there is an enhancement in Ip by about 1.6 times for a V-shaped well over a square well. Furthermore, in the case of a V-shaped well, the negative differential resistance occurs in a shorter voltage range, which may beneficial for ultra-fast switching and high-frequency signal generation. Our work anticipates the suitability of graphene, having better design flexibility, to develop ideally 2D RTDs for use in ultra-dense nano-electronic circuits and systems.

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“…Most of the state of art double barrier resonant tunneling diode (RTD) devices are made of heterojunctions of different materials. Hence, the expected performance of these RTD devices degrades over time due to interface quality issues including dislocations and lattice mismatch [9,10]. In contrast, AGNR RTD devices, alike two understudy platforms of this paper, are constructed by a single material avoiding any interface problem.…”

Section: Introductionmentioning

confidence: 99%

“…Graphene nanoribbons (GNRs) have a number of advantages over conventional 3D semiconductors [3,[9][10][11]. Most of the state of art double barrier resonant tunneling diode (RTD) devices are made of heterojunctions of different materials.…”

Section: Introductionmentioning

confidence: 99%

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Effects of uniaxial strain on the performance of armchair graphene nanoribbon resonant tunneling diode

Zoghi¹,

Kabir

2019

Semicond. Sci. Technol.

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Electronic performance of armchair graphene nanoribbon (AGNR) resonant tunneling diodes (RTDs) is influenced by strain effects, when they are mounted on the stretchable substrates or mechanically deformed due to real working conditions. Therefore, it is important to investigate how uniaxial strain can impact the performance of AGNR RTDs. In this paper, two platforms of AGNR RTD namely width-modified AGNR RTD and field-modified AGNR RTD are introduced and they are under both compressive and tensile uniaxial strain. It is found that the characteristics of AGNR RTD change considerably under either compressive or tensile strain. In particular, peak to valley ratio (PVR) can be totally deteriorated upon strong enough whole-body strain. However, local strain in the channel and barrier regions, in contrast to whole-body strain, can even improve the efficiency of AGNR RTD devices. Furthermore, the behavior of strained AGNR RTD is investigated while the width of device is modified. Numerical tight binding coupled with non-equilibrium Green's function is derived for this study to calculate corresponding Hamiltonian matrices and transport properties.

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Negative differential resistance in new structures based on graphene nanoribbons

Cited by 14 publications

References 42 publications

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

Performance enhancement of armchair graphene nanoribbon resonant tunneling diode using V-shaped potential well

Effects of uniaxial strain on the performance of armchair graphene nanoribbon resonant tunneling diode

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