Free-charge carrier parameters of n-type, p-type and compensated InN:Mg determined by Infrared Spectroscopic Ellipsometry

Infrared spectroscopic ellipsometry is applied to investigate the free-charge carrier properties of Mg-doped InN films. Two representative sets of In-polar InN grown by molecular beam epitaxy with Mg concentrations ranging from $1.2\times10^{17}$ cm$^{-3}$ to $8\times10^{20}$ cm$^{-3}$ are compared. P-type conductivity is indicated for the Mg concentration range of $1\times10^{18}$ cm$^{-3}$ to $9\times10^{19}$ cm$^{-3}$ from a systematic investigation of the longitudinal optical phonon plasmon broadening and the mobility parameter in dependence of the Mg concentration. A parameterized model that accounts for the phonon-plasmon coupling is applied to determine the free-charge carrier concentration and mobility parameters in the doped bulk InN layer as well as the GaN template and undoped InN buffer layer for each sample. The free-charge carrier properties in the second sample set are consistent with the results determined in a comprehensive analysis of the first sample set reported earlier [Sch\"oche et al., J. Appl. Phys. 113, 013502 (2013)]. In the second set, two samples with Mg concentration of $2.3\times10^{20}$ cm$^{-3}$ are identified as compensated n-type InN with very low electron concentrations which are suitable for further investigation of intrinsic material properties that are typically governed by high electron concentrations even in undoped InN. The compensated n-type InN samples can be clearly distinguished from the p-type conductive material of similar plasma frequencies by strongly reduced phonon plasmon broadening

Climate change, food supply, and dietary guidelines

Food production is affected by climate change, and, in turn, food production is responsible for 20–30% of greenhouse gases. The food system must increase output as the population increases and must meet nutrition and health needs while simultaneously assisting in achieving the Sustainable Development Goals. Good nutrition is important for combatting infection, reducing child mortality, and controlling obesity and chronic disease throughout the life course. Dietary guidelines provide advice for a healthy diet, and the main principles are now well established and compatible with sustainable development. Climate change will have a significant effect on food supply; however, with political commitment and substantial investment, projected improvements will be sufficient to provide food for the healthy diets needed to achieve the Sustainable Development Goals. Some changes will need to be made to food production, nutrient content will need monitoring, and more equitable distribution is required to meet the dietary guidelines. Increased breastfeeding rates will improve infant and adult health while helping to reduce greenhouse gases

Universality of electron accumulation at wurtzite c- and a-plane and zinc-blende InN surfaces

Electron accumulation is found to occur at the surface of wurtzite (112¯0), (0001), and (0001¯) and zinc-blende (001) InN using x-ray photoemission spectroscopy. The accumulation is shown to be a universal feature of InN surfaces. This is due to the low Г-point conduction band minimum lying significantly below the charge neutrality level

Awaking of ferromagnetism in GaMnN through control of Mn valence

Room temperature ferromagnetism of GaMnN thin films is awaked by a mild hydrogenation treatment of samples synthesized by molecular beam epitaxy. Local environment of Mn atoms is monitored by Mn-L2,3 near edge x-ray absorption fine structure (NEXAFS) technique. Doped Mn ions are present at substitutional sites of Ga both before and after the hydrogenation. No secondary phase can be detected. Major valency of Mn changes from +3 to +2 by the hydrogenation. The present result supports the model that the ferromagnetism occurs when Mn2+ and Mn3+ are coexistent and holes in the mid- gap Mn band mediate the magnetic coupling.Comment: 12 pages, 5 figure

Hydrogen in InN: A ubiquitous phenomenon in molecular beam epitaxy grown material

We study the unintentional H impurities in relation to the free electron properties of state-of-the-art InN films grown by molecular beam epitaxy (MBE). Enhanced concentrations of H are revealed in the near surface regions of the films, indicating postgrowth surface contamination by H. The near surface hydrogen could not be removed upon thermal annealing and may have significant implications for the surface and bulk free electron properties of InN. The bulk free electron concentrations were found to scale with the bulk H concentrations while no distinct correlation with dislocation density could be inferred, indicating a major role of hydrogen for the unintentional conductivity in MBE InN

Instrumentos de avaliação do aleitamento materno e seu uso na prática clínica

RESUMO Objetivos Identificar instrumentos de avaliação da amamentação e sua aplicação na prática clínica, validação e adaptação transcultural. Método Revisão integrativa, realizada em seis bases de dados e em uma biblioteca eletrônica, entre agosto/2014-dezembro/2015, sem limitação temporal. Resultados Foram identificados 19 instrumentos de avaliação do AM. Destes, 12 foram validados e cinco foram adaptados transculturalmente. Quanto à aplicação, destacam-se seu uso para a avaliação do risco de desmame (BAPT) e a percepção/comportamento da mulher em amamentar (BSES-SF e IIFAS). Conclusão A identificação dos instrumentos disponíveis e de suas indicações para a avaliação do AM pode auxiliar profissionais na escolha pelo instrumento a ser utilizado, qualificando a assistência materno-infantil