Numerical study on the optical and carrier recombination processes in GeSn alloy for E-SWIR and MWIR optoelectronic applications.

The Ge1-xSnx alloy is a promising material for optoelectronic applications. It offers a tunable wavelength in the infrared (IR) spectrum and high compatibility with complementary metal-oxide-semiconductor (CMOS) technology. However, difficulties in growing device quality Ge1-xSnx films has left the potentiality of this material unexplored. Recent advances in technological processes have renewed the interest toward this material paving the way to potential applications. In this work, we perform a numerical investigation on absorption coefficient, radiative recombination rate, and Auger recombination properties of intrinsic and doped Ge1-xSnx for application in the extended-short wavelength infrared and medium wavelength infrared spectrum ranges. We apply a Green's function based model to the Ge1-xSnx full electronic band structure determined through an empirical pseudopotential method and determine the dominant recombination mechanism between radiative and Auger processes over a wide range of injection levels.

Temperature characteristics of hot electron electroluminescence in silicon.

Emission spectra of avalanching n(+)p junctions manufactured in a standard CMOS technology with no process modifications were measured over a broad photon energy spectrum ranging from 0.8 eV to 2.8 eV at various temperatures. The temperature coefficients of the emission rates at different photon energies were determined. Below a photon energy of 1.35 eV the temperature coefficient of emission was positive, and above 1.35 eV the temperature coefficient was negative. Two narrowband emissions were also identified from the temperature characterization, namely an enhanced positive temperature coefficient at 1.15 eV photon energy, and an enhanced negative temperature coefficient at 2.0 eV. Device simulations and Monte Carlo simulations were used to interpret the results.

[Distribution, dissemination and removal of antibiotic resistant genes (ARGs) in the aquatic environment].

In recent years, the intensive use of antibiotics induces the development of antibiotic resistant genes (ARGs), which is an increasingly critical problem affecting human health, and the potential toxic effects of the ARGs have drawn great attention all over the world. This review gave an overview of the occurrence, potential sources, fate and ecological risks of ARGs in the environment. What's more, the removal of ARGs by different treatment processes such as sludge digestion, constructed wetland, disinfection and advanced treatments were assessed, and the improving directions of different treatment processes were also pointed out. Additionally, the highlights in need for further research were proposed based on the current pollution status.