您选择的条件: Junxiong Guo
  • A power-free graphene mid-infrared photodetector array

    分类: 光学 >> 量子光学 提交时间: 2023-02-19

    摘要: Graphene plasmons can resonantly enhance the incident light absorption and offer a potential for tunable spectral selectivity for mid-infrared (MIR) detection. High-performance tunable graphene plasmonic devices are, however, typically based on electrode-patterned graphene, which requires high power input and are technologically challenging in compact assembly. Here we demonstrate a tunable MIR photodetector array operating at zero input bias voltage. Our devices consist of integrating monolayer graphene with periodically "type-printed" ferroelectric superdomain. The spatial graphene carrier density patterns can be readily modulated by artificially defined ferroelectric superdomain with periodic nanoscale-wide stripe domains, achieving nonuniform pattering of conductivity and subsequently enabling graphene plasmons excitation and confinement for a selective transmission resonance in MIR regime. A high photoresponsivity of ~30 mA W-1 at room temperature is achieved in our device. We also observe that our device array features a tunable detection performance with spectral selectivity from 7.2 to 8.5 {\mu}m by directly reconfiguring the periodicity of ferroelectric superdomain. Our strategy could lead to the development of smart fabrication of on-chip MIR photodetector array for application of tunable spectral systems with low-energy consumption.

  • Ferroelectric superdomain controlled graphene plasmon for tunable mid-infrared photodetector with dual-band spectral selectivity

    分类: 光学 >> 量子光学 提交时间: 2023-02-19

    摘要: Dual-band infrared photodetectors (DBIPs) can discriminate desired signals from complex scenes and thus are highly expected for threat-warning, remote sensing, and astronomy applications. Conventional DBIPs with high-performances are, however, typically based on semiconductor thin films, but remain the challenges of complex spatial align, expensive growth and cooling requirement. Here, we report a tunable graphene plasmonic photodetector with dual-band infrared spectral selectivity driven by ferroelectric superdomain. The periodic ferroelectric polarization array with nanoscale ring shapes provides ultrahigh electrostatic field for spatially doping of monolayer graphene to desired patterns, and is further used to excite and confine intrinsic graphene plasmons. Our devices exhibit tunable resonance photoresponse in both two bands of 3.7-16.3 um and 15.1-52.1 um. The numerical calculations show that our devices own ultrahigh responsivities of 667-1080 A W-1 at room temperature in range of 5-50 um. Our devices make possible the applications of infrared imaging system and both stationary and motion state of objects detection. These investigations provide a novel approach for advanced infrared system construction by employing simple, low-cost, uncooling multispectral detectors array.

  • Tunable plasmonic devices by integrating graphene with ferroelectric nanocavity

    分类: 光学 >> 量子光学 提交时间: 2023-02-19

    摘要: Graphene plasmons are able to become the fundermental of novel conceptual photonic devices, resulting from their unique characteristics containing excitation at room temperature and tunable spectral selectivity in different frequencies. The pursuit of efficiently exciting and manipulating graphene plasmons is necessary and significant for high-performance devices. Here, we investigate graphene plasmon wave propagating in ferroelectric nanocavity array. We experimentally show that the the periodic ferroelectric polarizations could be used for doping graphene into desired spatial carrier density patterns. Based on a theoretical model that considers periodic ununiform conductivity across graphene sheet, the simulation results show surface plasmon polaritons (SPP) in graphene can be excited by an incident light in a similar way to the excitation of photonic crystal resonant modes. The graphene SPP resonance can be tuned from ~720 to ~1 000 cm-1 by rescaling the ferroelectric nanocavity array, and from ~540 to ~780 cm-1 by dynamically changing the applied gate voltage. Our strategy of graphene carrier engineering to excite SPP offers a promissing way for large-scale, non-destructive fabrication of novel graphene photonic devices.