Abstract Mid-infrared spectroscopy is a sensitive and selective technique for probing molecules in the gas or liquid phase. Investigating chemical reactions bio-medical applications such as drug production recently gaining particular interest. However, monitoring dynamic processes liquids commonly limited to bulky systems thus requires time-consuming offline analytics. In this work, we show next-generation, fully-integrated robust chip-scale sensor online measurements of molecule dynamics...

The properties of InAs quantum dots (QDs) have been studied for application in intermediate band solar cells. It is found that suppression plastic relaxation the QDs has a significant effect on optoelectronic properties. Partial capping plus annealing shown to be effective controlling height and suppressing relaxation. A force balancing model used explain relationship between QD height. strong luminescence observed from strained QDs, indicating presence localized states desired energy range....

InAs quantum dot multilayers have been grown using AlxGa1−xAs spacers with dimensions and compositions near the theoretical values for optimized efficiencies in intermediate band photovoltaic cells. Using an aluminium composition of x = 0.3 vertical 5 nm, transitions to energy close ideal value obtained. Optimum size uniformity density achieved by capping dots GaAs following indium-flush method. This approach has also resulted minimization crystalline defects epilayer structure.

In this paper, we show a superlattice quantum well infrared photodetector (S-QWIP) grown by metal-organic vapor phase epitaxy with two narrow photocurrent peaks in the mid range due to transitions between ground state from and excited states localized continuum. The structure composed of InGaAs/InAlAs quantum-well lattice matched InP central acting as an artificial defect. potential profile is carefully chosen explore parity anomaly continuum also reduce thermoexcited electrons decreasing...

InGaAs/InAlAs quantum well (QW) infrared photodetector structures have been investigated to reach operation energies larger than the heterostructure bandoffset. The are composed of superlattices having a central QW with thickness different from others, behaving as defect within periodic structure. gives rise localized states in continuum, allowing absorption and current generation for radiation beyond detection large 587 meV (2.11 μm) has achieved intrinsic intersubband transition ground...

The concept of leaky electronic states in the continuum is used to achieve room temperature operation photovoltaic superlattice infrared photodetectors. A structural asymmetric InGaAs/InAlAs potential profile designed create with preferential direction for electron extraction and, consequently, obtain at temperature. Due and virtual increase bandoffset, device presents both low dark current noise. Johnson noise limited specific detectivity reaches values as high 1.4 × 1011 Jones 80 K. At 300...

In this paper, we propose a system based on GaAs heterostructure where it is possible to generate photocurrent with mid-infrared radiation. This central quantum well (CQW) embedded in superlattice. Because of the CQW, which acts as defect, there are localized states between mini-bands continuum conduction band. Unlike usual systems final delocalized, oscillator strength due transitions electrons occupying ground-state these continuum-localized enhanced. An applied electrical bias mixes...

Abstract Herein, two challenges are addressed, which quantum well infrared photodetectors (QWIPs), based on III‐V semiconductors, face, namely: photodetection within the so‐called “forbidden gap”, between 1.7 and 2.5 microns, room temperature operation using thermal sources. First, to reach this forbidden wavelength range, a QWIP consists of superlattice structure with central (QW) different thickness is presented. The QW in symmetric structure, plays role defect otherwise periodic gives...

A combination of atomic force nanolithography and metal organic vapor phase epitaxy has been used to control the nucleation InAs nanostructures on InP substrates. Pits with controlled width depth were produced use nanolithography. The number nucleated depends applied is independent geometry pits. Study shows that density crystalline defects introduced by nanoindentation responsible for nanostructures.

We use the leaky electronic state in continuum concept to create a photovoltaic and photoconductive dual-mode operation superlattice infrared photodetector working at temperature as high room temperature. An asymmetric InGaAs/InAlAs is designed virtually increase material band offset localized with preferential direction for electron extraction. These two characteristics are responsible low dark current operating of device. At λp=4.1μm response peak, highest specific detectivity 5.7×1010...

Quantum dot intermediate band solar cells show great potential to outperform conventional tandem cells, but their performance is still far from the theoretically predicted expectations, mostly because of defects on quantum dots' layers. The influence thickness cap layer and temperature which sample subjected after its deposition - In flush figures merit InAs/GaAs based has been investigated. Cap layers 3 nm produce with improved merit, since thinner limits size QDs. Moreover, an increase by...

The use of epitaxial regrowth InP on lattice-matched In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.53</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.47</sub> As for passivation photodiodes lateral mesa surfaces is investigated. effect the regrown layer was examined by photoluminescence and dark current measurements compared with results obtained SiO xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Al O...

We study the dependence of chirp parameter on heavy- and light-hole energy splitting by analyzing change in absorption curve different InGaAs/InAlAs p-i-n multiple quantum well structures designed for use amplitude modulators. observe, transverse electric mode, a high sample whose fundamental transition involves light hole, whereas samples heavy more polarization sensitive are, smaller is. This indicates that it is not possible to have tensile strained electro-absorptive modulators which are...

Different InAs quantum dot structures grown on InGaAlAs lattice matched to InP were investigated for infrared photodetectors. Extremely narrow photocurrent peaks observed, demonstrating great potential fine wavelength selection. Structures which can detect radiation beyond 10μm developed. Polarization dependence measurements showed that the have a zero-dimensional character and are suitable detection of normal incident light. On other hand, containing coupled wells hybrid...

We present results from simulations of the photocurrent observed in recently fabricated InAs quantum dot infrared photodetectors that respond with strong resonance peaks ∼10μm wavelength range. The are good agreement experimental data generated earlier. Multiphoton scattering electrons localized dots not only accordance patterns, but also necessary to explain spectrum obtained calculations.

Multijunction solar cells hold the actual world record efficiency, converting 46% of energy into electricity on ground, and are very basis spatial missions' power supply. Multiple quantum well systems one possible solutions to overcome a major technological challenge this type device, namely, finding materials with appropriate bandgap lattice parameter that can lead current matching between stacked pn junctions. In work, as an alternative face issue, we present theoretical study...

The authors report on the development of quantum dot microdisk resonators grown by metal-organic chemical vapor deposition. Two stacked layers InAs dots embedded in a lattice-matched InGaAlAs (λg=1.47 μm) are (100) InP substrate. A new approach for fabrication active is developed using focused-ion beam (FIB) followed selective wet-chemical etching. Electrical and optical characterization resonator presented. Emission C-band at whispering-gallery modes observed.

InAs QDs embedded in an AlGaAs matrix have been produced by MOVPE with a partial capping and annealing technique to achieve controllable QD energy levels that could be useful for solar cell applications. The resulted spool-shaped are around 5 nm height log-normal diameter distribution, which is observed TEM range from 15 nm. Two photoluminescence peaks associated emission attributed the ground first excited states transitions. luminescence peak width correlated distribution of diameters...