ABSTRACTThe non-destructive estimation of doping concentrations in semiconductor devices is of paramount importance for many applications ranging from crystal growth to defect and inhomogeneity ...detection. A number of technologies (such as LBIC, EBIC and LPS) have been developed which allow the detection of doping variations via photovoltaic effects. The idea is to illuminate the sample at several positions and detect the resulting voltage drop or current at the contacts. We model a general class of such photovoltaic technologies by ill-posed global and local inverse problems based on a drift-diffusion system which describes charge transport in a self-consistent electrical field. The doping profile is included as a parametric field. To numerically solve a physically relevant local inverse problem, we present three approaches, based on least squares, multilayer perceptrons, and residual neural networks. Our data-driven methods reconstruct the doping profile for a given spatially varying voltage signal induced by a laser scan along the sample's surface. The methods are trained on synthetic data sets which are generated by finite volume solutions of the forward problem. While the linear least square method yields an average absolute error around 10%, the nonlinear networks roughly halve this error to 5%.
An efficient photoelectrode is fabricated by sequentially assembling 2.5 nm and 3.5 nm CdSe quantum dots (QDs) onto a TiO2 film. As revealed by UV-vis absorption spectroscopy, two sizes of CdSe QD ...can be effectively adsorbed on the TiO2 film. With a broader light absorption range and better coverage of CdSe QDs on the TiO2 film, a power conversion efficiency of 1.26% has been achieved for the TiO2/CdSe QD (2.5 nm)/CdSe QD (3.5 nm) cell under the illumination of one Sun (AM 1.5G, 100 mW cm(-2)). Electrochemical impedance spectroscopy shows that the electron lifetime for the device based on TiO2/CdSe QD (2.5 nm)/CdSe QD (3.5 nm) is longer than that for devices based on TiO2/CdSe QD (2.5 nm) and TiO2/CdSe QD (3.5 nm), indicating that the charge recombination at the interface is reduced by sensitizing with two kinds of CdSe QDs.
GaSb has been studied as a new alternative substrate for growing HgCdTe via molecular beam epitaxy (MBE). Cross-sectional transmission electron microscopy (TEM) studies indicate that MBE-grown CdTe ...buffer layers on GaSb have much lower misfit dislocation density than comparable layers grown on GaAs. The MBE-grown mid-wave infrared (MWIR) HgCdTe layers on GaSb substrates present material quality comparable to those grown on GaAs substrates, which is one of the state-of-the-art alternative substrates currently used to grow HgCdTe for the fabrication of MWIR detectors and focal plane arrays. Typically, HgCdTe materials grown on GaSb are found to have a rocking curve (double crystal x-ray diffraction) full width at half maximum of ~122 arcsec and an etch pit density of ~mid-10
6
cm
–2
. Electron backscatter diffraction mapping shows that the lattice misorientation/misfit dislocations near the HgCdTe/CdTe interface are negligible for GaSb substrates in comparison to GaAs substrates, and that the material quality of the HgCdTe layer on GaSb is determined primarily by the material quality of the CdTe buffer layer. These preliminary results are very encouraging considering that this is a relatively recent research effort, and higher quality MBE-grown HgCdTe materials are expected on GaSb substrates with further optimization of HgCdTe growth conditions as well as further improvements in the growth conditions for CdTe buffer layers.
The synthesis of nanocrystalline nickel by electrodeposition has been studied for more than 10 years. However, most attention has been on the adjustment of bath composition or development of new ...chemical additives. In this paper, a new method was developed to synthesize bulk nanocrystalline nickel without using any additives. Pulse plating with ultra narrow pulse width and high peak current density was employed to increase the deposition current density and the nucleation rate. At an on-time of 10 μs and an off-time of 90 μs, it was found that different surface morphologies, grain sizes, textures, and hardness were obtained at different current densities. Grain sizes ranging from 50 to 200 nm were obtained when the current density varied from 300 to 60 A
dm
−2. The preferred orientation of the nickel deposit changed from a weak (2
0
0) fiber texture to a strong (2
0
0) fiber texture when the peak current density increased from 40 to 100 A
dm
−2. It was obtained however that the intensity of the (2
0
0) fiber orientation decreased when there was a further increase in the current density. The hardness of the nickel deposit was also found to increase with increasing peak current density when it changed from 20 to 150 A
dm
−2, but the hardness tended to decrease when the current density was above 150 A
dm
−2. These experimental findings are considered to relate to the change in cathodic overpotential which affects both the grain size, the internal stress, the porosity, and the preferred orientation.
HgCdTe has dominated the high performance end of the IR detector market for decades. At present, the cost to fabricate HgCdTe based advanced infrared devices is relatively high. One approach to ...address this problem is to use cost effective alternative substrate, mainly Si and GaAs. Recently, GaSb has emerged as a new alternative with better lattice matching. In this paper, recent progress in molecular beam epitaxial (MBE) growth of HgCdTe infrared material at UWA is reported. HgCdTe has been grown on GaSb substrates by MBE, and has shown a lower Etch Pit Density (EPD) and higher minority carrier lifetime in comparison to other alternative substrates. This result makes GaSb an interesting and promising alternative substrate material for HgCdTe epitaxy.
•HgCdTe material is epitaxially grown by MBE on GaSb substrate.•Growth technologies for HgCdTe on GaSb are developed.•In comparison to other alternative substrates, higher HgCdTe material quality is observed.
This study systematically explore the efficacy and safety of fourth-generation chimeric antigen receptor T-cells (CAR-T), which express interleukin 7 (IL7) and chemokine C-C motif ligand 19 (CCL19) ...and target CD19, in relapsed or refractory large B-cell lymphoma.
Our center applied autologous 7×19 CAR-T combined with tirelizumab to treat 11 patients with relapsed or refractory large B-cell lymphoma. The efficacy and adverse effects were explored.
All 11 enrolled patients completed autologous 7×19 CAR-T preparation and infusion. Nine patients completed the scheduled six sessions of tirolizumab treatment, one completed four sessions, and one completed one session. Furthermore, five cases (45.5%) achieved complete remission, and three cases (27.3%) achieved partial remission with an objective remission rate of 72.7%. Two cases were evaluated for disease progression, and one died two months after reinfusion because of uncontrollable disease. The median follow-up time was 31 (2-34) months, with a median overall su
We report a localized surface plasmon enhanced upconversion luminescence in Au/SiO2/Y2O3:Yb3+,Er3+ nanoparticles when excited at 980 nm. By adjusting the silica spacer's thickness, a maximum ...9.59-fold enhancement of the green emission was obtained. Effect of the spacer distance on the Au-Y2O3:Yb3+, Er3+ green upconversion mechanism was numerically simulated and experimentally demonstrated. In theory for radiative decay and excitation rates, they can be largely enhanced at the spacer thicknesses of less than 70 and 75 nm, respectively, and the quenching can be caused by the non-radiative energy transferring at the distance of less than 55 nm.
An optofluidic system that uses the electrowetting technology to dynamically control the local surface plasmon resonance of the silver nanoparticle is invented. The silver nanoparticle is initially ...suspended at the interface of the polar liquid and the non-polar liquid. As the interface morphology changes with the applied voltage, the media distribution surrounding particle is changed accordingly, thus realizing the resonance absorption peak's modulation. The investigation result shows that a wide range of the spectral colors from red to blue can be selectively absorbed just by a single device. Specifically, when the radius of the particle is 50 nm, the wavelength of the absorption peak can be dynamically modulated from 460 nm to 607 nm. This proposed method can be used to design and prepare rapidly adjustable optical elements.
The aim of the present study was to investigate the potential role of Toll-like receptor 4 (TLR4) in lipopolysaccharide (LPS)-induced preterm delivery. Intraperitoneal injection of LPS in the ...presence or absence of previous TLR4 blockade was performed to establish a murine model of preterm delivery. The incidences of preterm delivery and fetal death were calculated. Flow cytometry was performed to examine the percentages of blood CD45+CD86+, CD3+CD69+, CD19+CD69+ and CD49b+CD69+ cell subsets, and the percentages of placenta CD45+CD86+, CD45+CD49b+ and CD49b+CD69+ cell subpopulations. In our study, an inflammation-induced preterm delivery model was established by intraperitoneal injection of LPS. Blocking TLR4 significantly decreased LPS-induced preterm delivery and fetal death. LPS treatment markedly up-regulated the percentages of blood CD45+CD86+, CD3+CD69+ and CD49b+CD69+ cells, and of placenta CD45+CD86+, CD45+CD49b+ and CD49b+CD69+ cells. TLR4 blockade almost completely abrogated LPS-induced elevated cell proportions. These data demonstrate that TLR4 plays a critical role in inflammation-induced preterm delivery.
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