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In this paper, a Ga2O3/diamond separate absorption and multiplication avalanche photodiode (SAM-APD) with mesa structure has been proposed and simulated. The simulation is based on an optimized Ga2O3/diamond heterostructure TCAD physical model, which is revised by repeated comparison with the experimental data of the literature. Since both Ga2O3 and diamond are ultra-wide bandgap semiconductor materials, the Ga2O3/diamond SAM-APD shows good solar-blind detection ability, and the corresponding cut off wavelength is about 263nm. The doping distribution and the electric field distribution of the SAM-APD are discussed, the simulation results show that the gain of the designed device can reach 5×104 and the peak responsivity can reach a value as high as 78 A/W.

International audience; We report on carrier dynamics in a spin photodiode based on a ferromagnetic-metal–GaAs tunnel junction. We show that the helicity-dependent current is determined not only by the electron spin polarization and spin asymmetry of the tunneling but in great part by a dynamical factor resulting from the competition between tunneling and recombination in the semiconductor, as well as by a specific quantity: the charge polarization of the photocurrent. The two latter factors can be efficiently controlled through an electrical bias. Under longitudinal magnetic field, we observe a strong increase of the signal arising from inverted Hanle effect, which is a fingerprint of its spin origin. Our approach represents a radical shift in the physical description of this family of emerging spin devices.

KangFuXinYe (KFX), the ethanol extract of the dried whole body of Periplaneta americana, is a well-known important Chinese medicine preparation that has been used to treat digestive diseases such as gastric ulcers for many years in China. However, its therapeutic effect and mechanism are not yet well understood. Thus, the aim of this study was to investigate the gastro-protective effects of KangFuXinYe (KFX) in indomethacin-induced gastric damage. Rats were randomly divided into six groups as follows: control, treated with indomethacin (35 mg·kg-1), different dosages of KFX (2.57, 5.14 and 10.28 mL·kg-1, respectively) plus indomethacin, and sucralfate (1.71 mL·kg-1) plus indomethacin. After treatment, rat serum, stomach and gastric homogenates were collected for biochemical tests and examination of histopathology firstly. Rat serum was further used for metabolomics analysis to research possible mechanisms. Our results showed that KFX treatment alleviated indomethacin-induced histopathologic damage in rat gastric mucosa. Meanwhile, its treatment significantly increased cyclooxygenase-1 (COX-1), prostaglandin E2 (PGE2) and epidermal growth factor (EGF) levels in rat serum and gastric mucosa. Moreover, KFX decreased cyclooxygenase-2 (COX-2) and interleukin-6 (IL-6) levels. Nine metabolites were identified which intensities significantly changed in gastric damage rats, including 5-hydroxyindoleacetic acid, indoxylsulfuric acid, indolelactic acid, 4-hydroxyindole, pantothenic acid, isobutyryl carnitine, 3-methyl-2-oxovaleric acid, sphingosine 1-phosphate, and indometacin. These metabolic deviations came to closer to normal levels after KFX intervention. The results indicate that KFX (10.28 mL·kg-1) exerts protective effects on indomethacin-induced gastric damage by possible mechanisms of action (regulating tryptophan metabolism, protecting the mitochondria, and adjusting lipid metabolism, and reducing excessive indomethacin).

Aucklandiae Radix (AR) and Vladimiriae Radix (VR) were used to treat gastrointestinal, liver and gallbladder diseases at practice. In most conditions, VR was used to be a substitute of AR or a local habit may attribute to the same main active ingredients Costunolide and Dehydrocostus lactone, which presented many similar pharmacological activities. However, other different lactone compounds in AR and VR also play a role in disease treatment, so the difference in therapeutic effects of AR and VR in related diseases needs to be further studied.Revealing the differences between the chemical compounds of the total lactone extracts of AR and VR (TLE of AR and VR) and the differences in the protective effects of cholestatic liver injury to ensure rational use of AR and VR.The macroporous adsorption resin was used to purify and enrich the lactone compounds to obtain the total lactone extracts of AR and VR. HPLC-PDA was used to obtain the data to establish chemical fingerprint and chemometric analysis to compare similarities and differences between TLE of AR and VR. The pharmacodynamic experiment revealed how TLE of AR and VR to show protect effects on cholestatic liver injury.Similarity analysis results showed TLE of AR and VR had a high similarity (0.9). Nevertheless, difference analysis results showed 4 compounds, Costunolide, Dehydrocostus lactone, 3β-acetoxy-11β-guaia-4 (15), 10 (14)-diene-12,6α-olide and vladinol F may contribute to the differences between them. The pharmacodynamics experiments results showed the TLE of AR and VR affected the different liver cholate-associated transporters mRNA expression (TLE of AR up-regulated CYP7A1, TLE of VR down-regulated FXR and BSEP), the TLE of AR and VR had an effect to regulate biochemical indicators (AST, ALT, ALP, TBA) of liver function, and TLE of VR was better than TLE of AR in reducing the expression of inflammatory factors (IL-6 and IL-1β).The liver protection of AR and VR have been confirmed, but the differences of material basis and mechanism of drug efficacy needed further study to guarantee formulation research and provide theoretical references for clinical rational applications of AR and VR.

Quantum cascade lasers (QCLs) suffer from catastrophic failure caused by serious self-heating, thus limiting their output power and working stability. In this study, we observed a distinctive failure morphology on the back facet of watt-level power QCL emitting at λ ∼ 7.7 µm. The failure was caused by a massive localized current and the channel of the massive current can be observed in the cavity. Because the massive current significantly increased temperature nearby, two burned holes were formed around the channel. A 3D thermal model shows that the back facet is a vulnerable location for failure because light absorption by the high-reflectance metal coating increases the facet temperature significantly. However, the starting point of the massive current has a certain distance from the facet which is the hottest location in the cavity. Therefore, we conduct a hypothesis that the cause of the massive current is thermal strain relaxations induced by temperature gradient. We calculated the positions of the relaxation points and one of them correspond with the failure starting point found experimentally. The strain relaxation damaged the active region, thus leading to the formation of the massive current.

Using activated carbon (AC) with nano- lithium iron phosphate (LiFePO 4 ) as the positive and hard carbon (HC) as the negative, this type lithium-ion capacitor (LIC) has the inherent advantages in rate characteristics, cycle life and chemical stability, which is more suitable for rail transit application. As an indicator of capacitor available energy, state of energy (SOE) is of great importance to estimate. However, most of the models utilized in the literature concerning state estimation of LIC become problematic for outlining the characteristics without considering wide current magnification. In this work, a method, which is considering wide current magnification, is proposed for state of energy estimation of LIC.

Aspergillus niger CJ-1 was applied to conduct fermentation process on tartary buckwheat leaves (TBL), and effect of fermentation time on antioxidant ability and chemical compositions was revealed. Antioxidant ability of TBL showed a three-stage change tendency during fermentation, which was relatively consistent with change in chemical compositions. Rutin and quercetin were identified as remarkable contributors among fermentation. Both total polyphenols, rutin and quercetin was positively being correlated with antioxidant activity of TBL. Results indicated that fermentation time influenced antioxidant activity by altering content of TBL phenolic compounds, which showed a three-stage change law: augmenting at the early stage of fermentation, declining at the medium stage of fermentation, and slightly changing during the last stage. This tendency suggested that fermentation was a potent means to promote antioxidant capacity of agro-food unless fermentation time was controlled. This study may provide a theoretical basis for producing fermented foods with high bioactivity.

Phlorizin (PHZ), a type of dihydrochalcone widely found in Rosaceae such as apples, is the first compound discovered as a sodium-glucose cotransporter (SGLT) inhibitor. It has been confirmed to improve the symptoms of diabetes and diabetic complications effectively. Like other flavonoids, the bioavailability challenge of PHZ is the wide phase I and II metabolism in the digestive tract. In this study, we investigated the pharmacokinetics and contribution of phase II metabolism after the oral and intravenous administrations of PHZ in rats having type 2 diabetes (T2D) and in normal rats. The phase II metabolism characteristics of PHZ were investigated by treating plasma samples with β-glucuronidase/sulfatase. The contribution ratio of phase II metabolism of PHZ ranged from 41.9% to 69.0% after intravenous injection with three doses of PHZ in normal rats. Compared with the observations for normal rats, AUC0-t and Cmax of PHZ significantly increased and T1/2 of PHZ significantly decreased in T2D rats. PHZ was converted into phloretin (PHT) through an enzyme-catalyzed hydrolysis reaction, and PHT was further transformed into conjugates with glycose after both oral and intravenous administrations. Moreover, it was found that the bioavailability of PHZ was about 5% in T2D rats, which was significantly higher than that in normal rats (0%). In conclusion, compared with the observations for normal rats, the pharmacokinetic characteristics of PHZ significantly changed in T2D rats through oral and intravenous administrations. The bioavailability of PHZ significantly increased in T2D rats. Besides, the phase II metabolites of PHT were the major existing forms in blood after oral and intravenous administrations. Our results indicated that the phase II metabolism characteristics of PHZ should be considered when PHZ is applied for the treatment of diabetes as a drug or functional food.

Periplaneta americana is one of the common traditional Chinese medicines, which has a long application history. It can tonify spleen, promote blood circulation, induce diuresis to alleviate edema, and promote granulation. It is clinically used for the treatment of alimentary canal diseases, chronic heart failure, cutaneous lesion, periodontitis and other diseases. There are some representative prescriptions, such as Kangfu Xinye, Xinmailong injection, Ganlong capsule, and Xiaozheng Yigan tablet. This paper reviewed the chemical components, pharmacological effects and clinical applications of P. americana, firstly summarized standards for the quality control of P. americana, found out and analyzed the key problems in the research. The aim of this paper is to provide the references for the further development and application of P. americana.

Natural products generally contain complex and multiple bioactive compounds that are responsible for the effects on health through complicated synergistic and/or suppressive actions. As an important raw material of local ethnic minority tea, ethnomedicines and food supplements in southwestern areas of China, Docynia indica (Wall.) Decne (DID) mainly consists of phlorizin (PHZ), which is the main active component. In this study, the holistic activities and the interactions of components of PHZ, non-phlorizin (NP) in the DID extract (DIDE) were evaluated. A rapid and effective high-speed counter-current chromatography (HSCCC) was performed to knock out PHZ from DIDE and the purity of PHZ was 96.01% determined by HPLC, with a recovery rate of 96.76%. After 13 weeks of treatment course in a high-fat diet (HFD)-induced obese mice model, the results revealed that the DIDE and PHZ significantly decreased weight gain, blood lipid levels, hyperplasia of adipocytes and alleviated inflammation (p &lt, 0.05). Both DIDE and PHZ improves insulin resistance (p &lt, 0.001). Meanwhile, the intestinal barrier function was improved compared to HFD group, through the determination of serum lipopolysaccharides (LPS), glucagon-likepeptide-2 (GLP-2) and hematoxylin-eosin staining of jejunum. Interestingly, after NP treatment, the metabolic syndrome of the HFD-induced obesity appeared to have a similar improvement. All the experiments showed that there is a synergistic weakening phenomenon when PHZ and NP interact with each other in the mixed state. In conclusion, for the PHZ and NP showing a good effect on anti-obesity, anti-inflammation, and intestinal barrier function, DIDE could be a good source of functional food to prevent obesity.

Silicon film as a surface passivation layer is reported to reduce surface recombination on silicon nanowires (SiNWs) and thus enable to improve SiNW solar cell (SC) performance. A question yet to be answered regards the link between the silicon film assets and the solar cell performances. We investigated the effect of the properties of silicon films on the SiNWs SC performances by adjusting hydrogen dilution. Our results showed that the open-circuit voltage (Voc) and short-circuit current density (Jsc) of SiNWs SC increase until hydrogen dilution 10 and then decrease. An open-circuit voltage of 0.397 V and short-circuit current density of 18.42 mA/cm2 are achieved at optimized hydrogen dilution. Based on the analysis of silicon film properties we proposed that the increase of defect density with hydrogen dilution was the main cause for the deterioration of SiNWs SC performance.

We reported a ligand- and additive-free Cu(OAc)2/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a broad range of primary and secondary benzylic alcohols, primary and secondary 1-heteroaryl alcohols, cinnamyl alcohols, and aliphatic alcohols to the corresponding aldehydes and ketones. This ambient temperature oxidation protocol is of practical features like aqueous acetonitrile as solvent, ambient air as the terminal oxidant, and low catalyst loading, presenting a potential value in terms of both economical and environmental considerations. Based on the experimental observations, a plausible reaction mechanism was proposed.

We reported an efficient ligand-free Co(OAc)2·4H2O/NaOH/O2/ethylene glycol reaction system that enables selective aerobic oxidation of a wide range of substrates covering 2,6-di-EWG-, 2,3,6-tri-EWG-, 2-EWG-, and 2-EWG-6-EDG-substituted 4-cresols into the corresponding 4-hydroxybenzaldehydes. Based on the experimental investigations and well-defined p-benzoquinone methides, a plausible reaction mechanism was proposed. Considering the simplicity of the procedure and importance of the products, the methodology was expected to become a favorable and practical tool in related benzylic C(sp3)–H functionalization chemistry.

High power and high brightness InP based lasers around 2 µm are attractive for many applications due to their intrinsic compatibility with photonic integrated circuits. However, high output power and low lateral divergence are difficult to be realized simultaneously with the traditional ridge waveguide structure. In this paper, we demonstrate significantly enhanced performance of 1.96 µm InP based InGaAs quantum well lasers by tapered waveguide structures. The double-channel waveguide laser with a straight waveguide section and a small-angle tapered optical amplifier section showed fundamental transverse mode lasing with an excellent beam quality. In agreement with our designed waveguide structures, the devices’ lateral divergence is remarkably reduced. For the device with a 3° tapered angle, the narrowest full width at half maximum (FWHM) of 8.2° of the far-field distribution is realized and the continuous-wave output power, measured at 25 °C, is increased up to 40 mW, which is much higher than the 12 mW of the laser with only a straight ridge waveguide.

In this paper, Methods of SOC estimation of Extended Kalman Filter (EKF) is studied based on the characteristics of Nickel-Metal Hydride (Ni-MH) battery pack with 120 cells in series and 8Ah capacity for HEV. In the study of EKF-based SOC estimation, the improved Thevenin circuit model is adopted, and a new hybrid pulse power characterization （HPPC） test is designed to identify the model parameters by using piecewise linear regression method. In this way, the precision of the circuit model is improved. In addition, The Kalman gain matrix is optimized for EKF iterative algorithm by two ways: a constant gain is increased taking into account the entire process; a dynamic gain which increases at the beginning of abrupt change and decreases rapidly after abrupt change is set up. The improvement achieves a good tracing prediction.

Quantum dots infrared photodetectors (QDIPs) theoretically have several advantages compared with quantum wells infrared photodetectors (QWIPs). In this paper, we discuss the theoretical advantages of QDIPs including the normal incidence response, lower dark current, higher responsivity and detectivity, etc. Recent device fabrication and experiment results in this field are also presented. Based on the analysis of existing problems, some approaches that would improve the capability of the device are pointed out.

To heteroepitaxally grow the crystalline cubic-GaN (c-GaN) film on the substrates with large lattice mismatch is basically important for fabricating the blue or ultra-violet laser diodes based on cubic group III nitride materials. We have obtained the crystalline c-GaN film and the heteroepitaxial interface between c-Gan and GaAs(001) substrate by the ECR Plasma-Assisted Metal Organic Chemical Vapor Deposition (PA-MOCVD) under low-pressure and low-temperature (∼600°C) on a homemade ECR-plasma Semiconductor Processing Device (ESPD). In order to decrease the growth temperature, the ECR plasma source was adopted as the activated nitrogen source, therefore the working pressure of MOCVD was decreased down to the region less than 1 Pa. To eliminate the damages from energetic ions of current plasma source, a Multi-cusp cavity-coupling ECR Plasma source (MEP) was selected to use in our experiment. To decrease the strain and dislocations induced from the large lattice mismatch between c-GaN and GaAs substrate, the plasma pretreatment procedure i.e., the initial growth technique was investigated. The experiment arrangements, the characteristics of plasma and the growth procedure, the characteristics of c-GaN film and interface between c-GaN and GaAs(001), and the roles of ECR plasma are described in this contribution.

A practical Cu(II)/TEMPO-catalyzed process oxidizes primary and secondary alcohols to the corresponding carbonyl compounds using air as the terminal oxidant.

We reported an efficient ligand-free Co(OAc)2·4H2O/NaOH/O2/ethylene glycol reaction system that enables selective aerobic oxidation of a wide range of substrates covering 2,6-di-EWG-, 2,3,6-tri-EWG-, 2-EWG-, and 2-EWG-6-EDG-substituted 4-cresols into the corresponding 4-hydroxybenzaldehydes. Based on the experimental investigations and well-defined p-benzoquinone methides, a plausible reaction mechanism was proposed. Considering the simplicity of the procedure and importance of the products, the methodology was expected to become a favorable and practical tool in related benzylic C(sp3)–H functionalization chemistry.

We propose a novel superluminescent diode (SLD) with a quantum dot (QD) active layer, which should give a wider output spectrum than a conventional quantum well SLD. The device makes use of inhomogeneous broadness of gain spectrum resulting from size inhomogeneity of self-assembled quantum dots grown by Stranski– Krastanow mode. Taking a design made out in the InxGa1-xAs/GaAs system for example, the spectrum characteristics of the device are simulated realistically, 100–200 nm full width of half maximum of output spectrum can be obtained. The dependence of the output spectrum on In composition, size distribution and injection current of the dots active region is also elaborated.

To explore the influence of borneol on intestinal absorption of muscone in rats.An in situ intestinal circulation perfusion experiment was used to study the changes in intestinal absorption kinetics of muscone before and after being compatible with borneol.Compared with the muscone group (MG), the absorption rate constants (Ka), the half-life period (T1/2) and the absorption rate (A) of muscone in the borneol + muscone group (BMG) were on the rise, but with no significant difference; after being compatible with borneol for a long period, Ka, T1/2 and A in the last borneol on muscone group (LBMG) increased, with significant difference (P0.05). in duodenum, LBMG showed better effects than MG (T1/2, P0.05); and so did in jejunum (Ka, P0.05; T1/2, P0.05); in ileum, there was no significant statistical difference between LBMG and MG.Borneol can promote the intestinal absorption of muscone in rats to some extent.

OBJECTIVE To establish the method for determining muscone in rat intestinal perfusate by GC-MS/MS and study its intestinal absorption kinetic characteristics in rats. METHOD The GC-MS/MS method was used to determine the content of muscone in rat intestinal circulation fluid. In situ intestinal circulation perfusion was adopted to study absorption kinetics of muscone in rats. RESULT Muscone was proved to be well absorbed in each section of small intestine. Its absorption rate constants (Ka) and the absorption rate (A) in the rat intestine showed duodenum > jejunum (P ileum (P < 0.01). Its Ka, A and t1/2 in rat small intestine was 0.990 h(-1) , 43.58% and 0.705h, respectively. CONCLUSION Muscone was well absorbed in each intestinal section, with duodenum better than jejunum (Ka, T1/2, P < 0.05) significantly better than ileum (Ka, T1/2, P < 0.01; A, P < 0.05). There is no obvious statistical difference between jejunum and ileum.

There have been considerable interests in methane detection based on infrared absorption spectroscopy for industrial and environment monitoring. The authors report on the realization of photoacoustic detection of methane (CH4) using mid-infrared distributed-feedback quantum cascade laser (DFB-QCL). The absorption line at 1316.83 cm(-1) was selected for CH4 detection, which can be reached by the self-manufactured DFB-QCL source operating in pulsed mode near 7.6 microm at room-temperature. The CH4 gas is filled to a Helmholtz resonant photoacoustic cell, which was equipped with a commercial electret microphone. The DFB-QCL was operated at 234 Hz with an 80 mW optical peak power. A detection limit of 189 parts per billion in volume was derived when the signal-to-noise ratio equaled 1.

Infrared detection within the atmospheric window between 3 to 5μm has gained great interest because of its wide range of applications, such as eye-safe free-space optical communication links and high-precision time-of-flight measurements used in 3D imaging. In this letter, we report on the characteristics of two InP-based strain-compensated InGaAs/InAlAs quantum cascade detectors (QCDs) detecting around 4 μm and 4.5 μm, which are promising candidates for applications in this wavelength range. Maximal responsivity values of 11.43mA/W at 180K and 10.1 mA/W at 78K and Johnson noise limited detectivities of 2.43×10 10 and 2×10 10 Jones at 78K, for the 4.5 μm and the 4 μm device, respectively, were obtained. In addition, both devices can work up to room temperature with responsivities of 0.81 mA/W(4.5μm) and 1.64 mA/W(4μm).

To study the optimum paper-roast conditions of Radix Vladimiriae.The contents of naphtha and costunolide and dehydrcostuslactone were used as estimated indexes. The paper-roast process of Radix Vladimiriae was studied by orthogonal design.The optimum condition was adding moderate water and marinates firstly, after getting rid of the water and experimenting 6 hours' closed lay, cutting Radix Vladimiriae into slices with 10 centimeters and drying under natural condition. One layer paper by one layer Radix Vladimiriae slice roasted 2 hours at 120 degrees C.The paper-roast process is stable, controllable and can provide referenced foundation for the production of paper-roast Radix Vladimiriae.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • The absorption of valacyclovir presents a highly negative correlation with the level of P-glycoprotein expression. • It has been confirmed that a polymorphism of the MDR1 gene in exon 26 is related to the level of P-glycoprotein expression in intestine. • This study was conducted to find the relationship between polymorphism of MDR1 gene and absorption of valacyclovir. WHAT THIS STUDY ADDS • Linkage disequilibrium exists between G2677T/A in exon 21 and C3435T in exon 26, between C1236T in exon 12 and C3435T, but not between C1236T and G2677T/A of MDR1 gene in the Chinese Han ethnic population. • Three single nucleotide polymorphisms of MDR1 gene do not influence the absorption of valacyclovir in the healthy Chinese Han ethnic population. AIMS To investigate the influence of three single nucleotide polymorphisms (SNPs) in exon 12 (C1236T), exon 21 (G2677T/A) and exon 26 (C3435T) of MDR1 gene on the absorption of valacyclovir after a single oral administration in the Chinese Han ethnic population. METHODS Two hundred healthy Chinese subjects were genotyped for the SNPs of C1236T, G2677T/A and C3435T in the MDR1 gene using allele-specific polymerase chain reaction. Linkage disequilibrium (LD) was analysed. Twenty-four subjects derived from a large random sample (n = 200) received a single oral dose of 600 mg valacyclovir. Plasma concentrations of acyclovir were determined up to 14 h after administration to obtain a pharmacokinetic profile. RESULTS LD existed between G2677T/A in exon 21 and C3435T in exon 26 (P 0.05). Cmax, AUC0–1.5 h and AUC0–∞ were used as indices of valacyclovir absorption. AUC0–∞ for the 2677TA genotype was 17.45 ± 2.40 µg × h/ml, which was much higher compared with the 2677GG, GA and TT genotypes of 10.44 ± 1.00, 11.84 ± 2.83, 11.34 ± 2.32 µg × h/ml, respectively (P 0.05). CONCLUSIONS Three SNPs of MDR1 gene did not influence the absorption of a single oral dose of 600 mg valacyclovir in healthy Chinese Han ethnic subjects.

Self-assembled InAs quantum dots were prepared on GaAs(100) substrate in a solid source molecular beam epitaxy system. The distribution and topographic images of uncapped dots were studied by atomic force microscope. The statistical result shows that the quantum dots are bimodal distribution. The photoluminescence spectrum results shows that the intensity of small size quantum dots dominated, which may be due to: (1) the state density of large quantum dots lower than that of small quantum dots; (2) the carriers capture rate of large size quantum dots is small relative to that of small ones; (3) there is a large strain barrier between large quantum dots and capping layer, and the large strain is likely to produce the defect and dislocation, resulting in a probability of carriers transferring from large quantum dots to small dots that is very small with temperature increasing.

GaAs grown under Ga-rich conditions often contains two dominant deep levels, sometimes referred to as the A and B levels. The authors have investigated the electronic properties of these levels in n-type and p-type material. The apparent activation energies for thermal hole emission were measured over eight orders of magnitude of thermal emission rate, and found to be 0.40 eV for level A and 0.70 eV for level B after the T2 correction. All four optical cross sections have been determined. The thresholds for electron excitation are 1.15 and 0.90 eV for the A and B levels, respectively, at 80K. A photocapacitance method is used to demonstrate that the two levels are coupled and thus due to one single defect. The electronic properties, in combination with the conditions under which the defect is formed, lead to the suggestion that the defect may be the GaAs antisite.

Photocapacitance measurements were used to study the photoionization cross‐section spectra of holes in iron doped Alx Ga1−xAs. The spectra are well described by the crystal field theory giving a nearly constant crystal field splitting of about 0.36 eV for all compositions studied. As a result of an extended range of composition (0≤x≤0.76), it was possible to show that the binding energy of the dominant iron center increases linearly with composition and that the relative position of the center is not related to any of the conduction band minima. The variation of the energy for Γ1(5E)→Γ5(5T2) transition in Fe2+(3d6) is discussed for different host crystals.

DLTS spectra of deep level impurities in semiconductors often display anomalies such as zero offsets, steps or peaks with reversed signs. For a correct interpretation of the spectra it is important to understand those features. They are explained here, and shown to be related to the presence of free-carrier tails which extend into the depletion region of a semiconductor junction. Gold-doped silicon and the so-called A - and B -levels in GaAs are chosen for illustration of the effects.

Our investigations of one iron- and two copper-related deep acceptor levels in the semiconductor alloy AlGaAs show that the opticalthreshold energies have the same linear composition dependence for all three levels. The particular nonexponential transient behaviour for thermal emission of carriers can be explained by a model in which the energy levels are broadened. A broadening mechanism due to random alloying is suggested.

A photocapacitance method was used to monitor the time dependences of the occupation numbers for the gold‐related donor and acceptor in silicon during optical excitation. The experimental data give strong evidence that the donor level corresponds to the +/0 transition and the acceptor to the 0/− transition for one single defect.

Concentration measurements using the electron paramagnetic resonance (EPR) signature of the Ni3+ (3d7) state in GaP have been compared with thermal emission and photocapacitance data measured on the same samples. These data combined with EPR photo-quenching measurements provide a definitive assignment of a state with a thermal activation energy for hole emission of 510 meV to the Ni3+ to Ni2+ transition. The optical threshold for the same transition is 520 meV and the cross section for thermal capture of a hole into Ni2+ is 1.3*10-16 cm2 at 240K.