Polarization-sensitive surface plasmon Schottky detectors

Abstract

A polarization detector based on the excitation of surface plasmon polaritons on the periodically corrugated metal surface of Schottky structures is presented. The surface modes are only excited by light having the appropriate polarization; they are leaky at the metal-semiconductor interface and are thus radiated into the semiconductor, where they generate charge carriers. By this mechanism the photocurrent of the device is enhanced and depends strongly on the polarization angle of the incident light. By use of two detectors with different grating orientations the polarization of the light can be determined unambiguously.

Surface plasmon photodetectors and their applications

“…A grating can be used as an alternative to a prism to increase the in‐plane momentum of the incident beam in order to match that of the SPP offering compactness and manufacturing advantages over the latter. A corrugated metal surface or an array of metal nanowires on a metal‐oxide‐metal (tunnel) structure , a metal‐semiconductor (Schottky) structure , a metal‐oxide‐semiconductor structure , or a commercial photodiode , have been investigated to implement SPP detectors (or solar cells ).…”

“…A corrugated detector combines a semiconductor structure with a corrugated metal grating designed to couple incoming optical waves to SPPs. One such structure is shown in Fig.…”

“…One such structure is shown in Fig. (a) . This structure consists of a top Al electrode on a thin SiO 2 layer (3 nm) on p‐Si, formed as a sinusoidal corrugated grating of height H , period Λ and grating vector k G = x 2π/ Λ ( x is the x ‐directed unit vector).…”

Surface plasmon enhanced optoelectronics

“…A grating-coupled SPP detector typically combines a Schottky detector with a grating designed to couple incoming light to SPPs [5]. p-polarised light incident onto the structure couples to SPPs propagating on the grating when momentum conservation is satisfied.…”

“…Grating-coupled SPP detectors are sensitive to the angle of incidence, polarisation and wavelength of the incident light. The polarisation sensitivity can be exploited in an arrangement of two detectors to determine the polarisation angle of normally-incident linearly-polarised light [5]. SPPs on grating detectors were also used to increase the absorptance in the metal contact of Schottky detectors exploiting IPE to increase their responsivity [6].…”