Graphene is one of the most popular material due to its promising properties, for instance electronics applications. Graphene films were grown on silicon carbide (SiC) substrate using chemical vapor deposition (CVD). Influence of the deposition temperature on the morphology of the films was investigated. Characterizations were done by reflectance mapping, atomic force microscopy and Raman spectroscopy. Two samples were done by sublimation process, to compare the number of layers and the morphology of the graphene films with the one grown by chemical vapor deposition.The reflectance mapping showed that the number of layers on the samples made by CVD was notinfluenced by the deposition temperature. But also, demonstrated that sublimation growth is present in allthe samples due to the presence of silicon coating in the susceptor. The growth probably started by sublimation and then CVD deposition. The step morphology characteristic of the silicon carbide substrate surface was conserved during the deposition of graphene. But due to surface step bunching, a decrease inthe step height occurred and the width of the terraces increased. The decreasing in deposition temperature leads to a smoother surface with the CVD method. Raman spectroscopy confirmed the presence ofgraphene and of the buffer layer characteristic of the sublimation growth. Moreover, it demonstrated the presence of compressive strain in the graphene layers.

Light reflectance from plants can be used as a non-invasive predictor of health and yield for many cropping systems, and has been investigated to a lesser extent with managed turfgrass systems. The frequent agronomic inputs associated with maintaining golf course grasses allow for exceptional stand quality under harsh growing conditions, but often expend resources inefficiently, leading to either stand loss or unnecessary inputs in localized areas. Turfgrass researchers have adopted some basic principles of light reflectance formerly developed for cropping systems, but field radiometric-derived narrow-band algorithms for turfgrass-specific protocols are lacking. Research was conducted to expand the feasibility of using radiometry to detect various turfgrass stressors and improve speed and geographic specificity of turfgrass management. Methods were developed to detect applied turfgrass stress from herbicide five days before visible symptoms developed under normal field growing conditions. Soil volumetric water content was successfully estimated using a water band index of creeping bentgrass canopy reflectance. The spectral reflectance of turfgrass treated with conventional synthetic pigments was characterized and found to erroneously influence plant health interpretation of common vegetation indices because of near infrared interference by such pigments. Finally, reflectance data were used to estimate root zone temperatures and root depth of creeping bentgrass systems using a gradient of wind velocities created with turf fans. Collectively, these studies provide a fundamental understanding of several turfgrass-specific reflectance algorithms and support unique opportunities to detect stresses and more efficiently allocate resources to golf course turf. / Ph. D.