Graphene mechanical oscillators with tunable frequency

Abstract

in the city of New York, USA 4 Samsung-SKKU Graphene Center (SSGC), Suwon, Gyeonggi 440-746, Korea †These authors contributed equally to this work Oscillators, which produce continuous periodic signals from direct current power, are central to modern communications systems, with versatile applications such as timing references and frequency modulators 1-7 . However, conventional oscillators typically consist of macroscopic mechanical resonators such as quartz crystals, which require excessive off-chip space. Here we report oscillators built on micron-size, atomically-thin graphene nanomechanical resonators, whose frequencies can be electrostatically tuned by as much as 14%.The self-sustaining mechanical motion of the oscillators is generated and transduced at room temperature by simple electrical circuitry. The prototype graphene voltage controlled oscillators exhibit frequency stability and modulation bandwidth sufficient for modulation of radio-frequency carrier signals. As a demonstration, we employ a graphene oscillator as the active element for frequency modulated signal generation, and achieve efficient audio signal transmission. 1 arXiv:1612.04019v1 [cond-mat.mes-hall]

Advanced Scanning Probe Microscopy of Graphene and Other 2D Materials

“…Thus, new concepts are required for modeling these materials. The coupling between piezoelectric polarization and semiconductor properties, such as electronic transport and photoresponse, is expected to give rise to unprecedented device characteristics [137,138]. The emerging fields of piezotronics and piezo-phototronics, which propose new means of manipulating charge-carrier transport in the operation of flexible devices through the application of external mechanical stimuli [139], demonstrate the need for the correlative characterization of mechanical and electronic properties at the single layer level, therefore opening new opportunities for the unceasing development of SPMs.…”

Direct and parametric synchronization of a graphene self-oscillator

“…3,10 Figure 2(a) shows such a plot for the freely running oscillator, where the phase diffuses after a few hundred microseconds. 16 In contrast, when the reference signal is applied (panel (b)), the phase is coherent during the measurement ($ 1 ms). This demonstrates that the oscillator is synchronized to the reference signal.…”

La visión de la nanotecnología para las radiocomunicaciones en los próximos años. Una perspectiva desde la academia

“…A través de las investigaciones dirigidas por (Chen, et al, 2013) y (Nguyen, 2005) de la Universidad de Columbia, fue posible el diseño, construcción y puesta en marcha de un nanooscilador mecánico de grafeno, para la sintonización de frecuencias en FM.…”

“…Los osciladores que producen señales periódicas continuas de potencia en corriente directa son el centro de los sistemas de comunicaciones modernos, con aplicaciones versátiles que incluyen referencias de temporización y moduladores de frecuencia (Chen, et al, 2013) y (Hajimiri, et al, 1999) Así mismo, la estructura de los osciladores convencionales suele estar conformada por resonadores mecánicos macroscópicos, algunos con cristales de cuarzo (los cuales requieren un mayor espacio y por lo general fuera del chip). A diferencia de estos osciladores, construidos en micrómetros de tamaño, los resonadores nanomécanicos de grafeno de un grosor atómico alcanzan frecuencias que pueden ser electrostáticamente afinadas hasta en un 14%, en las que un movimiento mecánicamente autosostenible se genera y transduce a temperatura ambiente en estos osciladores usando un simple circuito eléctrico (Hajimiri, et al, 1999) y (Nguyen, 2005).…”