5 research outputs found
Unexpected Aspects of Strain Relaxation and Compensation in InGaAs Metamorphic Structures Grown by MOVPE
We present a selection of stack designs
for MOVPE grown In<sub><i>x</i></sub>Ga<sub>1–<i>x</i></sub>As
metamorphic buffer layers following various convex-down compositional
continuous gradients of the In content, showing that defect generation
and strain can be managed in a variety of ways, some rather unexpected
(and unreported). Indeed, we observe that it is possible to grow surprisingly
thick tensile strained layers on metamorphic substrates, without significant
relaxation and defect generation. We believe our findings give significant
insights to the investigation of strain, relaxation, and defect distribution
in metamorphic buffer design, so to obtain properly engineered/tailored
structures (the most successful ones already finding applications
in device growth)
Hot-Electron Injection in Au Nanorod–ZnO Nanowire Hybrid Device for Near-Infrared Photodetection
In this Letter, we present a new
class of near-infrared photodetectors
comprising Au nanorods–ZnO nanowire hybrid systems. Fabricated
hybrid FET devices showed a large photoresponse under radiation wavelengths
between 650 and 850 nm, accompanied by an “ultrafast”
transient with a time scale of 250 ms, more than 1 order of magnitude
faster than the ZnO response under radiation above band gap. The generated
photocurrent is ascribed to plasmonic-mediated generation of hot electrons
at the metal–semiconductor Schottky barrier. In the presented
architecture, Au-nanorod-localized surface plasmons were used as active
elements for generating and injecting hot electrons into the wide
band gap ZnO nanowire, functioning as a passive component for charge
collection. A detailed investigation of the hot electron generation
and injection processes is discussed to explain the improved and extended
performance of the hybrid device. The quantum efficiency measured
at 650 nm was calculated to be approximately 3%, more than 30 times
larger than values reported for equivalent metal/semiconductor planar
photodetectors. The presented work is extremely promising for further
development of novel miniaturized, tunable photodetectors and for
highly efficient plasmonic energy conversion devices
Supplementary document for 100 Gbps PAM4 ultra-thin photodetectors integrated on SOI platform by micro transfer printing - 6642949.pdf
Proof-read supplement documen
Supplementary document for 100 Gbps PAM4 ultra-thin photodetectors integrated on SOI platform by micro transfer printing - 6635941.pdf
Revised supplementary document is attache
Direct visualization of phase-matched efficient second harmonic and broadband sum frequency generation in hybrid plasmonic nanostructures
Second harmonic generation and sum frequency generation (SHG and SFG) provide effective means to realize coherent light at desired frequencies when lasing is not easily
achievable. They have found applications from sensing to quantum optics and are of
particular interest for integrated photonics at communication wavelengths. Decreasing the
footprints of nonlinear components while maintaining their high up-conversion efficiency
remains a challenge in the miniaturization of integrated photonics. Here we explore
lithographically defined AlGaInP nano (micro)structures/ Al2O3/Ag as a versatile platform
to achieve efficient SHG/SFG in both waveguide and resonant cavity configurations in both
narrow- and broadband infrared (IR) wavelength regimes (1300–1600nm). The effective
excitation of highly confined hybrid plasmonic modes at fundamental wavelengths allows
efficient SHG/SFG to be achieved in a waveguide of a cross-section of 113nm×250nm, with a mode area on the deep subwavelength scale (λ2/135) at fundamental wavelengths.
Remarkably, we demonstrate direct visualization of SHG/SFG phase-matching evolution in the waveguides. This together with mode analysis highlights the origin of the improved
SHG/SFG efficiency. We also demonstrate strongly enhanced SFG with a broadband IR source by exploiting multiple coherent SFG processes on 1µm diameter AlGaInP disks/Al2O3/Ag with a conversion efficiency of 14.8%MW−1 which is five times the SHG value using the narrowband IR source. In both configurations, the hybrid plasmonic structures exhibit >1000 enhancement in the nonlinear conversion efficiency compared to their photonic counterparts. Our results manifest the potential of developing suchnanoscale hybrid plasmonic devices for state-of-the-art on-chip nonlinear optics applications