Plasmon resonant amplification of a hot electron-driven photodiode  

作　　者：Lang Shen Nirakar Poudel George N. Gibson Bingya Hou Jihan Chen Haotian Shi Ernest Guignon William D. Page Arturo Pilar Stephen B. Cronin 

机构地区：[1]Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA [2]Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA [3]Department of Physics, University of Connecticut, Storrs, CT06269, USA [4]Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA [5]Ciencia Inc., East Hartford, CT 06108, USA [6]Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA

出　　处：《Nano Research》2018年第4期2310-2314,共5页纳米研究（英文版）

摘　　要：We report plasmon resonant excitation of hot electrons in a photodetector based on a metal/oxide/metal （Au/Al2O3/graphene） heterostructure. In this device, hot electrons, excited optically in the gold layer, jump over the oxide barrier and are injected into the graphene layer, producing a photocurrent. To amplify this process, the bottom gold electrode is patterned into a plasmon resonant grating structure with a pitch of 500 nm. The photocurrent produced in this device is measured using 633-nm-wavelength light as a function of incident angle. We observe the maximum photocurrent at ＋10° from normal incidence under irradiation with light polarized parallel to the incident plane （p-polarization） and perpendicular to the lines on the grating, and a constant （angle-independent） photocurrent under irradiation with light polarized perpendicular to the incident plane （s-polarization） and parallel to the grating. These data show an amplification factor of 4.6× under resonant conditions. At the same angle （±10°）, we also observe sharp dips in the photoreflectance corresponding to wavevector matching between the incident light and the plasmon mode in the grating. In addition, finite-difference time-domain simulations predict sharp dips in the photoreflectance at ±10°, and the electric field intensity profiles show clear excitation of a plasmon resonant mode when illuminated with p-polarized light at this angle.We report plasmon resonant excitation of hot electrons in a photodetector based on a metal/oxide/metal （Au/Al2O3/graphene） heterostructure. In this device, hot electrons, excited optically in the gold layer, jump over the oxide barrier and are injected into the graphene layer, producing a photocurrent. To amplify this process, the bottom gold electrode is patterned into a plasmon resonant grating structure with a pitch of 500 nm. The photocurrent produced in this device is measured using 633-nm-wavelength light as a function of incident angle. We observe the maximum photocurrent at ＋10° from normal incidence under irradiation with light polarized parallel to the incident plane （p-polarization） and perpendicular to the lines on the grating, and a constant （angle-independent） photocurrent under irradiation with light polarized perpendicular to the incident plane （s-polarization） and parallel to the grating. These data show an amplification factor of 4.6× under resonant conditions. At the same angle （±10°）, we also observe sharp dips in the photoreflectance corresponding to wavevector matching between the incident light and the plasmon mode in the grating. In addition, finite-difference time-domain simulations predict sharp dips in the photoreflectance at ±10°, and the electric field intensity profiles show clear excitation of a plasmon resonant mode when illuminated with p-polarized light at this angle.

关 键 词：hot electrons plasmonic resonance PLASMON GRATING PHOTOCURRENT NON-EQUILIBRIUM 

分 类 号：TN364.2[电子电信—物理电子学] TQ323.5[化学工程—合成树脂塑料工业]