Low-bias flat band-stop filter based on velocity modulated gaussian graphene superlattice

Sattari-Esfahlan, S. M.; Shojaei, S.

doi:10.1016/j.ssc.2017.08.005

Cited by 8 publications

(8 citation statements)

References 26 publications

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“…29,30 It is also possible to have a tunable band-stop filter by modulating the Fermi veolicty barriers and the external bias voltage in non-conventional fashion. 31 As we have corroborated much attention has been paid to create and modulate stop bands in graphene superlattices. However, for superlattice devices pass bands are as important as stop bands.…”

Section: Introductionsupporting

confidence: 61%

“…To get the stop-band enlargement it is fundamental that the bandgaps of the constituent superlattices overlap. Another possibility are aperiodic and non-conventional gapped graphene heterostructures 29–31 . In this case, the omnidirectional electronic bandgap associated to gapped graphene can be extended by appropriately choosing the widths of the potentials of the constituent superlattices 29,30 .…”

Section: Introductionmentioning

confidence: 99%

“…Another possibility are aperiodic and non-conventional gapped graphene heterostructures. [29][30][31] In this case, the omnidirectional electronic bandgap associated to gapped graphene can be extended by appropriately choosing the widths of the potentials of the constituent superlattices. 29,30 It is also possible to have a tunable band-stop filter by modulating the Fermi veolicty barriers and the external bias voltage in non-conventional fashion.…”

Section: Introductionmentioning

confidence: 99%

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Non-conventional graphene superlattices as electron band-pass filters

Sánchez-Arellano

Madrigal-Melchor

Rodrı́guez-Vargas

2019

Sci Rep

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Electron transmission through different non-conventional (non-uniform barrier height) gated and gapped graphene superlattices (GSLs) is studied. Linear, Gaussian, Lorentzian and Pöschl-Teller superlattice potential profiles have been assessed. A relativistic description of electrons in graphene as well as the transfer matrix method have been used to obtain the transmission properties. We find that it is not possible to have perfect or nearly perfect pass bands in gated GSLs. Regardless of the potential profile and the number of barriers there are remanent oscillations in the transmission bands. On the contrary, nearly perfect pass bands are obtained for gapped GSLs. The Gaussian profile is the best option when the number of barriers is reduced, and there is practically no difference among the profiles for large number of barriers. We also find that both gated and gapped GSLs can work as omnidirectional band-pass filters. In the case of gated Gaussian GSLs the omnidirectional range goes from −50° to 50° with an energy bandwidth of 55 meV, while for gapped Gaussian GSLs the range goes from −80° to 80° with a bandwidth of 40 meV. Here, it is important that the energy range does not include remanent oscillations. On the light of these results, the hole states inside the barriers of gated GSLs are not beneficial for band-pass filtering. So, the flatness of the pass bands is determined by the superlattice potential profile and the chiral nature of the charge carriers in graphene. Moreover, the width and the number of electron pass bands can be modulated through the superlattice structural parameters. We consider that our findings can be useful to design electron filters based on non-conventional GSLs.

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Section: Introductionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Non-conventional graphene superlattices as electron band-pass filters

Sánchez-Arellano

Madrigal-Melchor

Rodrı́guez-Vargas

2019

Sci Rep

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“…Hence, the Fermi velocity is a proper factor to switch current through graphene barriers. [ 15 ] Quantized quasi‐energy states within the quantum well are observed in the energy range of 0.07–0.15 eV. Applying a bias voltage

V_{normalb} = 0.2 V

leads to spatially confined resonant states.…”

Section: Resultsmentioning

confidence: 99%

“…[ 1,4 ] In this regard, several reports demonstrated how the Fermi velocity alters graphene transport features [ 11–14 ] and its device performance. [ 15,16 ] Among graphene morphologies, quantum wells (QWs), [ 17,18 ] hetrostructures, [ 19–22 ] and superlattices (SLs) [ 23–26 ] have widely been implemented in designing/fabrication emerging devices [ 27–29 ] and exploring novel phenomenon [ 30–35 ] beyond the reach of exciting materials. In this context, resonant tunneling as one of the unique transport processes in SLs exhibited great promise to enrich the potential of SLs and QW devices including tunnel transistors (TFETs) [ 36–38 ] and resonant tunneling diodes (RTDs).…”

Section: Introductionmentioning

confidence: 99%

Fermi Velocity Modulation Induced Low‐Bias Negative Differential Resistance in Graphene Double Barrier Resonant Tunneling diode

2021

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Negative differential resistance (NDR) devices are adequate candidates for the functional devices applicable to the next‐generation integrated circuit technology so‐called “Beyond CMOS.” Here, a graphene velocity‐modulation‐barrier resonant‐tunneling diode operating at room temperature is proposed. The current–voltage characteristics of the device are analyzed using the non‐equilibrium Green's function technique. It is found that the Fermi velocity barrier in the well/barrier region manipulates the tunneling transmission probability by suppressing the Klein region and improving the resonant tunneling leading to NDR. For special values of velocity barriers, resonant states have maximum alignment with each other which increases peak current with a high peak to valley ratio (PVR). The width and the position of the NDR window are controlled and engineered by the device dimensions and the height of potential barriers. The smaller the device showed the better the NDR properties such as larger current density and maximum PVR. Taken together, the results reveal that adequate magnitude of the Fermi velocity in graphene barrier can be an impressive concept for the fabrication of emerging tunneling devices.

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