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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.

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.