Theoretical study of a group IV p–i–n photodetector with a flat and broad response for visible and infrared detection

We report a theoretical study of a broadband Si/graded-SiGe/Ge/Ge0.9Sn0.1 p–i–n photodetector with a flat response based on modulating thickness of the layers in the active region.The responsivity of the photodetector is about 0.57 A/W in the range of 700 to 1800 nm.This structure is suitable for silicon-based epitaxial growth.Annealing is technically applied to form the graded-SiGe.The photodetector reaches a cut-off wavelength at^2300 nm and a low dark-current density under 3 V reverse bias about 0.17 mA/cm^2 is achieved theoretical at room temperature.This work is of great significance for silicon-based detection and communication,from visible to infrared.

Comparative Study on the Effect of Mongolian Medicine Euphorbia pekinensis and Pharbitidis Semen(Black)

[Objectives]To explore the difference of purgative effect of Mongolian medicine Euphorbia pekinensis and Pharbitidis Semen(black)by animal experiment,taking Euphorbia pekinensis and Pharbitidis Semen(black)as the research object.[Methods]Sixty Kunming mice were randomly divided into blank group(n=20),Euphorbia pekinensis group(n=20)and Pharbitidis Semen(black)group(n=20).After fasted but provided with free acess to drinking water for 3 d,the mice were intragastrically administered with drinking water,Euphorbia pekinensis test solution and Pharbitidis Semen(black)test solution,respectively.The mice were then placed separately in a mouse cage covered with filter paper for purgation test and intestinal propulsion test.[Results]The time of the first purgation in the Euphorbia pekinensis group and the Pharbitidis Semen(black)group was longer than that in the blank group(P<0.05).The total times of purgation and defecation within 5 h in the Euphorbia pekinensis group and the Pharbitidis Semen(black)group were higher than those in the blank group(P<0.05);the purgation index and intestinal propulsion rate in the Euphorbia pekinensis group and the Pharbitidis Semen(black)group were higher than those in the blank group(P<0.05).[Conclusions]The Mongolian medicine Euphorbia pekinensis was similar to Pharbitidis Semen(black)in purgation test and intestinal propulsion test,and could play a substitute role.

Preliminary Discussion on Sand Therapy in Mongolian Medicine

Sand therapy of Mongolian medicine is one of traditional Mongolian medical treatments.It conducts heat energy to the human body through natural hot sand applied on the body,achieving the effect of preventing and curing disease.It is an external treatment method,characterized with easy operation,obvious curative effect and small side effects.Referring to the relevant literature of sand therapy in Mongolian medicine and combined with actual situation,the functions and use of sand therapy are summarized in this article,thereby providing theoretical basis and reference for research on sand therapy.

Electrical properties of Si/Si bonded wafers based on an amorphous Ge interlayer

An amorphous Ge（a-Ge） intermediate layer is introduced into the Si bonded interface to lower the annealing temperature and achieve good electrical characteristics. The interface and electrical characteristics of nSi/n-Si and p-Si/n-Si junctions manufactured by low-temperature wafer bonding based on a thin amorphous Ge are investigated. It is found that the bubble density tremendously decreases when the a-Ge film is not immersed in DI water. This is due to the decrease of the –OH groups. In addition, when the samples are annealed at 400 °C for20 h, the bubbles totally disappear. This can be explained by the appearance of the polycrystalline Ge（absorption of H;） at the bonded interface. The junction resistance of the n-Si/n-Si bonded wafers decreases with the increase of the annealing temperature. This is consistent with the recrystallization of the a-Ge when high-temperature annealing is conducted. The carrier transport of the Si-based PN junction annealed at 350 °C is consistent with the trap-assisted tunneling model and that annealed at 400 °C is related to the carrier recombination model.