The paper expounds relevant results of some of the present author’s experi- ments defining the strapdown IMU sensors’ errors and their propagation into and within DGPS/IMU. In order to deal with this problem, the author conducted both the laboratory and field-based experiments. In the landborne laboratory the stand-alone Low-Cost IMU MotionPak MKII was verified in terms of the accelerometer bias, scale factor, gyroscope rotation parameters and internal temperature cross-correlations. The waterborne field-trials based on board dedicated research ships at the lake and at the busy small sea harbour were augmented by the landborne ones. These experiments conducted during the small, average, and high dynamics of movement provided comparative sole- GPS, stand-alone DGPS and integrated DGPS/IMU solution error analysis in terms of the accuracy and the smoothness of the solution. This error estimation was also carried on in the context of the purposely-erroneous incipient DGPS/IMU initialisation and alignment and further in the circumstances of on-flight alignment improvement in the absence of the signal outages. Moreover, the lake-waterborne tests conducted during extremely low dynamics of movement informed about the deterioration of the correctly initialised DGPS/IMU solution with reference to the stand-alone DGPS solution and sole- GPS solution. The above-mentioned field experiments have checked positively the DGPS /MKI research integrating software prepared during the Polish/German European Union Research Project and modified during the subsequent Project supported by the Polish Committee for Scientific Research.

The advance of MEMS-based inertial sensors successfully expands their applications to small unmanned

aerial vehicles (UAV), thus resulting in the challenge of reliable and accurate in-flight alignment for airborne

MEMS-based inertial navigation system (INS). In order to strengthen the rapid response capability

for UAVs, this paper proposes a robust in-flight alignment scheme for airborne MEMS-INS aided by global

navigation satellite system (GNSS). Aggravated by noisy MEMS sensors and complicated flight dynamics,

a rotation-vector-based attitude determination method is devised to tackle the in-flight coarse alignment

problem, and the technique of innovation-based robust Kalman filtering is used to handle the adverse impacts

of measurement outliers in GNSS solutions. The results of flight test have indicated that the proposed

alignment approach can accomplish accurate and reliable in-flight alignment in cases of measurement outliers,

which has a significant performance improvement compared with its traditional counterparts.

The utmost limit performance of interband cascade detectors optimized for the longwave range of infrared radiation is investigated in this work. Currently, materials from the III–V group are characterized by short carrier lifetimes limited by Shockley-Read-Hall generation and recombination processes. The maximum carrier lifetime values reported at 77 K for the type-II superlattices InAs/GaSb and InAs/InAsSb in a longwave range correspond to ∼200 and ∼400 ns. We estimated theoretical detectivity of interband cascade detectors assuming above carrier lifetimes and a value of ∼1–50 μs reported for a well-known HgCdTe material. It has been shown that for room temperature the limit value of detctivity is of ∼3–4×10¹⁰ cmHz^1/2/W for the optimized detector operating at the wavelength range ∼10 μm could be reached.

The sensitivity of III-V-based infrared detectors is critically dependent upon the carrier concentration and mobility of the absorber layer, and thus, accurate knowledge of each is required to design structures for maximum detector performance. Here, measurements of the bulk in-plane resistivity, in-plane mobility, and carrier concentration as a function of temperature are reported for non-intentionally doped and Si-doped mid-wave infrared InAs0.91Sb0.09 alloy and InAs/InAs0.65Sb0.35 type-II superlattice materials grown on GaSb substrates. Standard temperature- and magnetic-field-dependent resistivity and the Hall measurements on mesa samples in the van der Pauw configuration are performed, and multi-carrier fitting and modelling are used to isolate transport of each carrier species. The results show that up to 5 carrier species of the surface, interface and bulk variety contribute to conduction, with bulk electron and hole mobility up to 2·105 cm2/V s and 8·103 cm2/V s, respectively and background dopant concentration levels were between 1014 and 1015 cm−3. The in-plane mobility temperatures dependence is determined and trends of each carrier species with temperature and dose are analysed.

The work presents doping characteristics and properties of high Si−doped InGaAs epilayers lattice−matched to InP grown by low pressure metal−organic vapour phase epitaxy. Silane and disilane were used as dopant sources. The main task of investigations was to obtain heavily doped InGaAs epilayers suitable for usage as plasmon−confinement layers in the construction of mid−infrared InAlAs/InGaAs/InP quantum−cascade lasers (QCLs). It requires the doping concentration of 1×10¹⁹ cm^–3 and 1×10²⁰ cm^–3 for lasers working at 9 μm and 5 μm, respectively. The electron concentration increases linearly with the ratio of gas−phase molar fraction of the dopant to III group sources (IV/III). The highest electron concentrations suitable for InGaAs plasmon−contact layers of QCL was achieved only for disilane. We also observed a slight influence of the ratio of gas−phase molar fraction of V to III group sources (V/III) on the doping efficiency. Structural measurements using high−resolution X−ray diffraction revealed a distinct influence of the doping concentration on InGaAs composition what caused a lattice mismatch in the range of –240 ÷ –780 ppm for the samples doped by silane and disilane. It has to be taken into account during the growth of InGaAs contact layers to avoid internal stresses in QCL epitaxial structures.

A robust Kalman filter improved with IGG (Institute of Geodesy and Geophysics) scheme is proposed and used to resist the harmful effect of gross error from GPS observation in PPP/INS (precise point positioning/inertial navigation system) tightly coupled positioning. A new robust filter factor is constructed as a three-section function to increase the computational efficiency based on the IGG principle. The results of simulation analysis show that the robust Kalman filter with IGG scheme is able to reduce the filter iteration number and increase efficiency. The effectiveness of new robust filter is demonstrated by a real experiment. The results support our conclusion that the improved robust Kalman filter with IGG scheme used in PPP/INS tightly coupled positioning is able to remove the ill effect of gross error in GPS pseudorange observation. It clearly illustrates that the improved robust Kalman filter is very effective, and all simulated gross errors added to GPS pseudorange observation are successfully detected and modified.

The design and performance analysis of a 1310/1550-nm wavelength division demultiplexer with tapered geometry based on InP/InGaAsP multimode interference (MMI) coupler has been carried out. Wavelength response of demultiplexer of conventional MMI and tapered input and tapered output (tapered I/O) waveguides geometry of the MMI have been discussed. The demultiplexing function has been first performed by choosing a suitable refractive index of the guiding region and geometrical parameters such as the width and length of MMI structure have been achieved. Access width of tapered I/O waveguides have been adjusted to give a low insertion loss (IL) and high extinction ratio (ER) for the considered wavelengths of 1310 nm and 1550 nm. The total size of the demultiplexer has been significantly reduced over the existing MMI devices. Numerical simulations with finite difference beam propagation method are applied to design and optimize the operation of the proposed demultiplexer.

The paper reports on the barrier mid-wave infrared InAs/InAsSb (x_Sb = 0.4) type-II superlattice detector operating below thermoelectrical cooling. AlAsSb with Sb composition, x_Sb = 0.97; barrier doping, N_D < 2×10¹⁶ cm⁻³ leading to valence band offset below 100 meV in relation to the active layer doping, N_D = 5×10¹⁵ cm⁻³ was proved to be proper material not introducing extra barrier in valence band in the analyzed temperature range in XBn architectures. The detectivity of the simulated structure was assessed at the level of ∼ 10¹¹ Jones at T ∼ 100 K assuming absorber thickness, d = 3 μm. The detector’s architecture for high frequency response operation, τ_s = 420 ps (T ∼ 77 K) was presented with a reduced active layer of d = 1 μm.

The paper presents noise measurements in low-resistance photodetectors using a cross-correlation-based transimpedance amplifier. Such measurements usually apply a transimpedance amplifier design to provide a current fluctuation amplification. In the case of low-resistance sources, the measurement system causes additional relevant system noise which can be higher than noise generated in a tested detector. It mainly comes from the equivalent input voltage noise of the transimpedance amplifier. In this work, the unique circuit and a three-step procedure were used to reduce the floor noise, covering the measured infrared detector noise, mainly when operating with no-bias or low-bias voltage. The modified circuit and procedure to measure the noise of unbiased and biased detectors characterized by resistances much lower than 100 Ω were presented. Under low biases, the reference low-resistance resistors tested the measurement system operation and techniques. After the system verification, noise characteristics in low-resistance InAs and InAsSb infrared detectors were also measured.

In this paper ∼16 μm-emitting multimode InP-related quantum cascade lasers are presented with the maximum operating temperature 373 K, peak and average optical power equal to 720 mW and 4.8 mW at 303 K, respectively, and the characteristic temperature (T₀) 272 K. Two types of the lasers were fabricated and characterized: the lasers with a SiO₂ layer left untouched in the area of the metal-free window on top of the ridge, and the lasers with the SiO₂ layer removed from the metal-free window area. Dual-wavelength operation was obtained, at λ ∼ 15.6 μm (641 cm⁻¹) and at λ ∼ 16.6 μm (602 cm⁻¹) for lasers with SiO₂ removed, while within the emission spectrum of the lasers with SiO₂ left untouched only the former lasing peak was present. The parameters of these devices like threshold current, optical power and emission wavelength are compared. Lasers without the SiO₂ layer showed ∼15% lower threshold current than these ones with the SiO₂ layer. The optical powers for lasers without SiO₂ layer were almost twice higher than for the lasers with the SiO₂ layer on the top of the ridge.

The authors report two approaches, the first based on growth of lattice matched InGaAs/GaAsSb superlattice on InP substrate with tunable bandgap in the 2 to 3 µm range. The second approach is based on bulk random alloy InGaAsSb, which is tunable from 1.7 µm to 4.5 µm and lattice matched to the GaSb lattice constant. In each case, detector structures were fabricated and characterised. The authors have assessed the performance of these materials relative to commercially available extended short wave infrared devices through comparison to IGA-Rule 17 dark current performance level. A complementary barrier structure used in the InGaAsSb design showed improved quantum efficiency. The materials compare favourably to commercial technology and present additional options to address the challenging extended short wave infrared spectral band.

Designing of a nanoscale Quantum Well (QW) heterostructure with a well thickness of ∼60 Å is critical for many applications and remains a challenge. This paper has a detailed study directed towards designing of In_0.29Ga_0.71As_0.99N_0.01/GaAs straddled nanoscale-heterostructure having a single QW of thickness ∼60 Å and optimization of optical and lasing characteristics such as optical and mode gain, differential gain, gain compression, anti-guiding factor, transparency wavelength, relaxation oscillation frequency (ROF), optical power and their mutual variation behavior. The outcomes of the simulation study imply that for the carrier concentration of ∼2 × 10¹⁸cm⁻³ the optical gain of the nano-heterostructure is of 2100 cm⁻¹ at the wavelength is of 1.30 μm. Though the obtained gain is almost half of the gain of InGaAlAs/InP heterostructure, but from the wavelength point of view the InGaAsN/GaAs nano-heterostructure is also more desirable because the 1.30 μm wavelength is attractive due to negligible dispersion in the silica based optical fiber. Hence, the InGaAsN/GaAs nano-heterostructure can be very valuable in optical fiber based communication systems.

The hierarchical structure of InSe<β-CD<FeSO₄>> composition with 4-fold grade expansion was synthesized with the intercalation-deintercalation technique. Electrical properties of the structure obtained were examined using impedance and thermostimulated current spectroscopy methods. Influence of temperature, static magnetic field and illumination on electrical properties of the synthesized compound was investigated. Changes in the impurity spectrum of the expanded hierarchical structure were analyzed and extraordinary magneto- and photoimpedance behavior of InSe<β-CD<FeSO₄>> at room temperature was explained.

Ga-free InAs/InAsSb type-II superlattice structures grown on GaSb substrates have demonstrated high performance for mid-wave infrared applications. However, realisation of long wavelength infrared photodetectors based on this material system still presents challenges, especially in terms of reduced quantum efficiency. This reduction is due, in part, to the increased type-II superlattice period required to attain longer wavelengths, as thicker periods decrease the wave-function overlap for the spatially separated quantum wells. One way to improve long wavelength infrared performance is to modify the type-II superlattice designs with a shorter superlattice period for a given wavelength, thereby increasing the wave-function overlap and the resulting optical absorption. Long wavelength infrared epitaxial structures with reduced periods have been realised by shifting the lattice constant of the type-II superlattice from GaSb to AlSb. Alternatively, epitaxial growth on substrates with orientations different than the traditional (100) surface presents another way for superlattice period reduction. In this work, the authors evaluate the performance of long wavelength infrared type-II superlattice detectors grown by molecular beam epitaxy using two different approaches to reduce the superlattice period: first, a metamorphic buffer to target the AlSb lattice parameter, and second, structures lattices matched to GaSb using substrates with different orientations. The use of the metamorphic buffer enabled a ~30% reduction in the superlattice period compared to reference baseline structures, maintaining a high quantum efficiency, but with the elevated dark current related to defects generated in the metamorphic buffer. Red-shift in a cut-off wavelength obtained from growths on high-index substrates offers a potential path to improve the infrared photodetector characteristics. Focal plane arrays were fabricated on (100), (311)A- and (211)B-oriented structures to compare the performance of each approach.

Mid-wavelength infrared detectors and focal plane array based on n-type InAs/InAsSb type-II strained layer superlattice absorbers have achieved excellent performance. In the long and very long wavelength infrared, however, n-type InAs/InAsSb type-II strained layer superlattice detectors are limited by their relatively small absorption coefficients and short growth-direction hole diffusion lengths, and consequently have only been able to achieve modest level of quantum efficiency. The authors present an overview of their progress in exploring complementary barrier infrared detectors that contain p-type InAs/InAsSb type-II strained layer superlattice absorbers for quantum efficiency enhancement. The authors describe some representative results, and also provide additional references for more in-depth discussions. Results on InAs/InAsSb type-II strained layer superlattice focal plane arrays for potential NASA applications are also briefly discussed.

This work investigates the potential of InAs/GaSb superlattice detectors for the short-wavelength infrared spectral band. A barrier detector structure was grown by molecular beam epitaxy and devices were fabricated using standard photolithography techniques. Optical and electrical characterisations were carried out and the current limitations were identified. The authors found that the short diffusion length of ~1.8 µm is currently limiting the quantum efficiency (double-pass, no anti-reflection coating) to 43% at 2.8 µm and 200 K. The dark current density is limited by the surface leakage current which shows generation-recombination and diffusion characters below and above 195 K, respectively. By fitting the size dependence of the dark current, the bulk values have been estimated to be 6.57·10−6 A/cm2 at 200 K and 2.31·10−6 A/cm2 at 250 K, which is only a factor of 4 and 2, respectively, above the Rule07.

In this paper, we present the electrical and electro-optical characterizations of an InAs/GaSb type-2 superlattice barrier photodetector operating in the full longwave infrared spectral domain. The fabricated detectors exhibited a 50% cut-off wavelength around 14 μm at 80 K and a quantum efficiency slightly above 20%. The dark current density was of 4.6 × 10 2 A/cm2 at 80 K and a minority carrier lateral diffusion was evaluated through dark current measurements on different detector sizes. In addition, detector spectral response, its dark current-voltage characteristics and capacitance-voltage curve accompanied by electric field simulations were analyzed in order to determine the operating bias and the dark current regimes at different biases. Finally, dark current simulations were also performed to estimate a minority carrier lifetime by comparing experimental curves with simulated ones.

The impact ionization in semiconductor materials is a process that produces multiple charge carrier pairs from a single excitation. This mechanism constitutes a possible road to increase the efficiency of the p-n and p-i-n solar cells junctions. Our study considers the structure of InN/InGaN quantum dot solar cell in the calculation. In this work, we study the effect of indium concentration and temperature on the coefficient of the material type parameter of the impact ionization process for a p(InGaN)-n(InGaN) and p(InGaN)- i(QDs-InN)-n(InGaN) solar cell. Next, we investigate the effect of perturbation such as temperature and indium composition on conventional solar cell’s (p(InGaN)-n(InGaN)) and solar cells of the third generation with quantum dot intermediate band IBSC (p(InGaN-i(QD-InN)-n(InGaN)) by analyzing their behaviour in terms of efficiency of energy conversion at the presence of the impact ionization process. Our numerical results show that the efficiency is strongly influenced by all of these parameters. It is also demonstrated that decreased with the increase of indium concentration and temperature which contributes to an overall improvement of the conversion efficiency.

In this work, we present findings on the syntheses and study of properties of InSe<PTHQ> nanohybrid. The introduction of guest component in GaSe matrix leads to an increase in inhomogeneities, which is clearly confirmed by the strengthening of the low-frequency horizontal branch of Nyquist diagrams. A constant magnetic field counteracts this effect and changes the behavior of the impedance hodograph at low frequencies to the opposite. Illumination leads to a colossal increase in quantum capacitance, which is clearly demonstrated in the Nyquist diagram. For the synthesized InSe<PTHQ> nanohybrid the interesting behavior of the current-voltage characteristic is reported. As a result of studies of the synthesized InSe<PTHQ> nanohybrid the effect of “negative capacity” is observed, the magnitude of which can be controlled by the electric field. Based on the constructed impedance model and proposed N-barrier model, the physical mechanisms of the investigated processes are suggested.

Many countries, including Indonesia, face severe water scarcity and groundwater depletion. Monitoring and evaluation of water resources need to be done. In addition, it is also necessary to improve the method of calculating water, which was initially based on a biophysical approach, replaced by a socio-ecological approach. Water yields were estimated using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model. The Ordinary Least Square (OLS) and geographic weighted regression (GWR) methods were used to identify and analyze socio-ecological variables for changes in water yields. The purpose of this study was: (1) to analyze the spatial and temporal changes in water yield from 2000 to 2018 in the Citarum River Basin Unit (Citarum RBU) using the InVEST model, and (2) to identify socio-ecological variables as driving factors for changes in water yields using the OLS and GWR methods. The findings revealed the overall annual water yield decreased from 16.64 billion m3 year-1 in the year 2000 to 12.16 billion m3 year-1 in 2018; it was about 4.48 billion m3 (26.91%). The socio-ecological variables in water yields in the Citarum RBU show that climate and socio-economic characteristics contributed 6% and 44%, respectively. Land use/Land cover (LU/LC) and land configuration contribution fell by 20% and 40%, respectively.The main factors underlying the recent changes in water yields include average rainfall, pure dry agriculture, and bare land at 28.53%, 27.73%, and 15.08% for the biophysical model, while 30.28%, 23.77%, and 10.24% for the socio-ecological model, respectively. However, the social-ecological model demonstrated an increase in the contribution rate of climate and socio-economic factors and vice versa for the land use and landscape contribution rate. This circumstance demonstrates that the socio-ecological model is more comprehensive than the biophysical one for evaluating water scarcity.

The paper presents the effect of ICP-RIE etching time using one-component plasma on various parameters of an InAs/GaSb type II superlattice matrix. In the studies, two samples used at different BCl3 gas flow rates were compared and it was found that using a lower flow rate of 7 sccm results in obtaining a smoother sidewall morphology. Next, five periodic mesa-shaped structures were etched under identical conditions, but using a different time. The results indicated that the ICP-RIE method using a BCl3 flow rate of 7 sccm, ICP:RIE power ratio of 300W:270W allowed the ICP:RIE formation of a periodic mesa-shaped structure with smooth and perpendicular sidewalls.

Autorka artykułu analizuje wpływ twórczości Marcela Prousta na utwory dramatyczne Tennessee Williamsa, zwłaszcza na dramat Szklana menażeria, znany także z hollywoodzkiej wersji filmowej. W sztuce tej ważną rolę odgrywają Proustowskie motywy, takie jak czas, pamięć i jej mechanizmy. Podobnie jak Proust, Williams nie ukrywa w swoim utworze elementów autobiograficznych. W Szklanej menażerii zwraca również uwagę inspirowane powieścią Prousta wykorzystanie motywów muzycznych oraz doszukiwanie się podobieństw między bohaterami literackimi a postaciami z dzieł malarskich. Choć Proust nie pisał dramatów, a Williams nie zostawił po sobie żadnej powieści, to łączyła ich miłość do teatru i przekonanie, że wspomnienie jest swego rodzaju spektaklem, a scena to szczególnie odpowiednie miejsce, by opowiadać o przeszłości.

In this study, an analysis of the optical performance of two types of distributed Bragg reflector structures based on GaAs and InP material systems was carried out. The structures were designed for maximum performance at 4 µm with their reflectivity achieving between 80 and 90% with eight pairs of constituent layers. To further enhance the performance of these structures, additional Au layers were added at the bottom of the structure with Ti pre-coating applied to improve the adhesivity of the Au to the semiconductor substrate. The optimal range of Ti layer thickness resulting in the improvement of the maximum reflectivity was determined to be in between 5 and 15 nm.

Dual-band infrared detector, which acquires more image information than single-band detectors, has excellent detection, recognition, and identification capabilities. The dual-band detector can have two bumps to connect with each absorber layer, but it is difficult to implement small pitch focal plane arrays and its fabrication process is complicated. Therefore, the most effective way for a dual-band detector is to acquire each band by bias-selectable with one bump. To aim this, a dual-band MWIR/LWIR detector based on an InAs/GaSb type-II superlattice nBn structure was designed and its performance was evaluated in this work. Since two absorber layers were separated by the barrier layer, each band can be detected by bias-selectable with one bump. The fabricated dual-band device exhibited the dark current and spectral response characteristics of MWIR and LWIR bands under negative and positive bias, respectively. Spectral crosstalk that is a major issue in dual-band detectors was also improved. Finally, a 20 μm pitch 640 × 512 dual-band detector was fabricated, and both MWIR and LWIR images exhibited an average noise equivalent temperature difference of 30 mK or less at 80 K.