Ge(Sn) nano-island/Si heterostructure photodetectors with plasmonic antennas

Abstract

We report on photodetection in deep subwavelength Ge(Sn) nano-islands on Si nano-pillar substrates, in which self-aligned nano-antennas in the Al contact metal are used to enhance light absorption by means of local surface plasmon resonances. The impact of parameters such as substrate doping and device geometry on the measured responsivities are investigated and our experimental results are supported by simulations of the three-dimensional distribution of the electromagnetic fields. Comparatively high optical responsivities of about 0.1 A W−1 are observed as a consequence of the excitation of localized surface plasmons, making our nano-island photodetectors interesting for applications in which size reduction is essential.

Light-Emission from Ion-Implanted Group-IV Nanostructures

“…photonic crystals (159,161,162,164) or microdisks [19,160] and microrings [160]. An improvement of the optical properties can also be based on plasmonic effects, by coupling the QD layer beneath the Si cap to a plasmonic nanoparticle that is deposited on top of the Si capping layer [166,167]. Naturally, for these resonator structures, no particular alignment to the QD positions is possible using self-assembled nanostructures.…”

Dual functional modes for nanostructured p-Cu2O/n-Si heterojunction photodiodes

“…where R is the responsivity of the PD and J dark is the dark current density. As it is not meaningful to determine the value for D * at zero bias because the dark current density must be zero, the detectivity is calculated to be 1.78×10 12 Hz 1/2 W −1 at −0.1 V bias. Obviously, the smaller the dark current is for a PD, the greater the sensitivity is to detect weak optical signals.…”

“…The device structure for MSM PDs is symmetrical so an external bias is required to separate electron-hole pairs. Schottky junction-type PDs are fast but have limited development opportunities because there is Fermi level pinning due to a large number of defects at the interfaces [10][11][12]. A p-n junction type PD allows a self-powered operation mechanism because a built-in potential separates electron-hole pairs [13].…”

Oblique Deposition of Ti/Pt/Au Electrode on Photonic Crystal for Vertical Current Injection

“…In this paper, we introduce the oblique deposition of electrodes to prevent metal materials from entering cladding layers or the core layer through the air holes of a PhC lattice. While the oblique deposition of metal for contacting nanostructured devices is an approach that has previously been utilized for the formation of contacts to optoelectronic devices containing arrays of semiconductor nanowires [22] or nanodots [23], this method has not been applied to 2-D photonic crystal with air holes before this study, as far as we know. We evaluate the specific contact resistance by the transmission line method.…”