Nanoimprinted Hybrid Metal-Semiconductor Plasmonic Multilayers with Controlled Surface Nano Architecture for Applications in NIR Detectors.

Akram Khosroabadi,Robert Norwood,Nasser Peyghambarian,Palash Gangopadhyay,Kyungjo Kim,Steven Hernandez

doi:10.3390/ma8085028

Akram Khosroabadi, Robert Norwood + Show 4 more

Open Access

https://doi.org/10.3390/ma8085028

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Abstract

We present a proof of concept for tunable plasmon resonance frequencies in a core shell nano-architectured hybrid metal-semiconductor multilayer structure, with Ag as the active shell and ITO as the dielectric modulation media. Our method relies on the collective change in the dielectric function within the metal semiconductor interface to control the surface. Here we report fabrication and optical spectroscopy studies of large-area, nanostructured, hybrid silver and indium tin oxide (ITO) structures, with feature sizes below 100 nm and a controlled surface architecture. The optical and electrical properties of these core shell electrodes, including the surface plasmon frequency, can be tuned by suitably changing the order and thickness of the dielectric layers. By varying the dimensions of the nanopillars, the surface plasmon wavelength of the nanopillar Ag can be tuned from 650 to 690 nm. Adding layers of ITO to the structure further shifts the resonance wavelength toward the IR region and, depending on the sequence and thickness of the layers within the structure, we show that such structures can be applied in sensing devices including enhancing silicon as a photodetection material.

Highlights

Surface plasmon resonance (SPR) refers to a collective, but localized, oscillation of the conduction electrons that appear at sharp features in metallic nanostructures when excited by an electromagnetic (EM) field [1,2,3]
They display extraordinary optical characteristics that are derived from the simultaneous existence and close coupling of localized surface plasmon resonance and semiconductor optoelectronic properties, as well as the synergistic interactions between the two components
By changing the dimensions and thicknesses of various layers, we show that the plasmon resonance can be tuned to achieve enhanced broadband absorption in the near infrared (NIR) and IR regimes

Summary

Introduction

Surface plasmon resonance (SPR) refers to a collective, but localized, oscillation of the conduction electrons that appear at sharp features (corners or edges) in metallic nanostructures when excited by an electromagnetic (EM) field [1,2,3]. Nonlocalization of SPs has been the key reason hybrid nanostructures composed of semiconductor transparent oxides and plasmonic metal components are receiving extensive attention They display extraordinary optical characteristics that are derived from the simultaneous existence and close coupling of localized surface plasmon resonance and semiconductor optoelectronic properties, as well as the synergistic interactions between the two components. In this paper we have fabricated and explored several alternative designs where a transparent conducting oxide layer, in particular, indium tin oxide (ITO), has been added underneath the plasmonic metal Ag to achieve nonlocal behavior of the plasmon resonance and enhanced broadband absorption. By changing the dimensions and thicknesses of various layers, we show that the plasmon resonance can be tuned to achieve enhanced broadband absorption in the NIR and IR regimes This is of particular interest for wavelengths over 1150 nm, the maximum operational wavelength for current Si avalanche photodiodes. We use FDTD simulations to probe the efficacy of these designs to control and achieve nonlocality in the surface plasmon resonance in the Ag layer

Discussion

Plasmon Hybridization Model

Surface Plasmon Excitation in Ag Nanopillars

Hybrid Metal and Metal Oxide Core Shell Nanostructured Arrays

FDTD Simulation

Conclusions