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We investigate the nonlinear optical properties of single resonant plasmonic antennas fabricated from heavily-doped Germanium films. Excitation with intense and ultrashort mid-infrared pulses at 10.8 μm wavelength produces emission at 3.7 μm via third-harmonic generation.
Germanium-on-silicon waveguides are designed, fabricated and characterized with a novel near-field infrared spectroscopy technique that allows on-chip investigation of the in-coupling efficiency. On-chip propagation along bends and straight sections up to 0.8 mm is demonstrated around λ = 6 μm.
The detection and amplification of molecular absorption lines from a chemical weapons simulant is demonstrated using plasmonic antennas fabricated from n-Ge epitaxially grown on Si. A free-standing Si0.25Ge0.75 microbolometer detector with n-Ge plasmonic antenna is demonstrated as an integrated mid-infrared plasmonic sensor.
Ge-on-Si has been demonstrated as a platform for Si foundry compatible plasmonics. We use laser thermal annealing to demonstrate activated doping levels >1020 cm−3 which allows most of the 3 to 20 μm mid-infrared sensing window to be covered with enhancements comparable to gold plasmonics.
Germanium-on-silicon rib waveguides are modelled, fabricated and characterized with a novel near-field infrared spectroscopy technique that allows on-chip investigation of the waveguide losses at 5.8 μm wavelength.
The detection and amplification of molecular absorption lines from a mustard gas simulant is demonstrated using plasmonic antennas fabricated from n-Ge epitaxially grown on Si. Approaches to integrated sensors will be presented along with a review of n-Ge compared to other mid-infrared plasmonic materials.
Recent advances in semiconductor film deposition allow for the growth of heavily-doped germanium with effective plasma frequencies above 60 THz, corresponding to wavelengths below 5 μm. This technology paves the way for mid-infrared nanoplasmonics with application in integrated telecommunication systems and enhanced molecular sensing in the so-called vibrational fingerprint spectral region [1].
We explore the nonlinear optical properties of plasmonic semiconductor antennas resonant in the mid infrared. The nanostructures are fabricated on silicon substrates from heavily doped germanium films with a plasma frequency of 30 THz, equivalent to a wavelength of 10 μm. Illumination with ultrashort pulses at 10.8 μm produces coherent emission at 3.6 μm via third-harmonic generation.
Despite the recent introduction of heavily-doped semiconductors for mid-infrared plasmonics, it still remains an open point whether such materials can compete with noble metals. We employ a whole set of figures of merit to thoroughly assess the use of heavily-doped Ge on Si as a mid-infrared plasmonic material and benchmark it against standard noble metals such as Au. In doing this, we design and...
Intersubband absorption from p-Ge quantum wells grown on Si is demonstrated. The absorption can be tuned by adjusting the quantum well thickness. FTIR transmission measurements on as-grown wafers show broad absorption at mid-infrared wavelengths.
We investigate the mid-infrared response of heavily doped germanium films and periodic arrays of nanoantennas by both continuous wave transmission/reflection spectroscopy and ultrafast pump-probe spectroscopy. We compare the data to finite-element modeling electromagnetic simulations of the subwavelength nanostructures. The plasma frequency of the doped or optically activated semiconductor extends...
The n-type Ge-on-Si epitaxial material platform enables a novel paradigm for plasmonics in the mid-infrared, prompting the future development of lab-on-a-chip and subwavelength vibrational spectroscopic sensors. In order to exploit this material, through proper electrodynamic design, it is mandatory to retrieve the dielectric constants of the thin Ge epilayers with high precision due to the difference...
We introduce an all-semiconductor platform for mid-infrared plasmonics based on epitaxial heavily-doped Ge-on-Si. We design, fabricate, and characterize plasmonic Ge antenna arrays to assess the potential of this platform for mid-infrared sensing applications.
The photoluminescence of process-induced tensile strained nanostructures fabricated using Ge on Si is reported. 100 nm pillars were etched and embedded in a silicon nitride thin film demonstrating photoluminescence emission up to ∼2.5 µm.
The design, modeling, fabrication, and characterization of single-photon avalanche diode detectors with an epitaxial Ge absorption region grown directly on Si are presented. At 100 K, a single-photon detection efficiency of 4% at 1310 nm wavelength was measured with a dark count rate of , resulting in the lowest reported noise-equivalent power for a Ge-on-Si single-photon...
Electroluminescence from strained n-Ge quantum wells LEDs on Si0.05Ge0.95 are demonstrated. Electroluminescence characterisation demonstrates two peaks around 1.55 µm and 1.8 µm, which correspond to transitions between the direct and indirect transitions respectively.
LEDs are reported from Ge-on-Si in which process induced strain has increased the emission wavelength. The direct bandgap electroluminescence emits up to ∼ µW of power between 1.6 µm and ∼1.8 µm, significantly larger than previous LEDs.
The fabrication and characterisation of LED structures made of Ge grown on Si substrates is reported. The structures are circular mesa of strained n-Ge etched down to an undoped buffer of Ge. The electroluminescence exhibit average power levels at 1.7 μm of 10 μW, many orders of magnitude larger than the nW previously reported. 3 individual mechanisms of emission are identified which can be used to...
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