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Experimental electronic structure of In2O3 and Ga2O3

2011, Janowitz, C., Scherer, V., Mohamed, M., Krapf, A., Dwelk, H., Manzke, R., Galazka, Z., Uecker, R., Irmscher, K., Fornari, R., Michling, M., Schmeißer, D., Weber, J.R., Varley, J.B., Van De Walle, C.G.

Transparent conducting oxides (TCOs) pose a number of serious challenges. In addition to the pursuit of high-quality single crystals and thin films, their application has to be preceded by a thorough understanding of their peculiar electronic structure. It is of fundamental interest to understand why these materials, transparent up to the UV spectral regime, behave also as conductors. Here we investigate In2O3 and Ga2O3, two binary oxides, which show the smallest and largest optical gaps among conventional n-type TCOs. The investigations on the electronic structure were performed on high-quality n-type single crystals showing carrier densities of ∼1019 cm-3 (In2O3) and ∼1017 cm-3(Ga2O3). The subjects addressed for both materials are: the determination of the band structure along high-symmetry directions and fundamental gaps by angular resolved photoemission (ARPES). We also address the orbital character of the valence- and conduction-band regions by exploiting photoemission cross.

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Microparticle Manipulation and Imaging through a Self-Calibrated Liquid Crystal on Silicon Display

2018-11-20, Zhang, Haolin, Lizana, Angel, Van Eeckhout, Albert, Turpin, Alex, Ramirez, Claudio, Iemmi, Claudio, Campos, Juan

We present in this paper a revision of three different methods we conceived in the framework of liquid crystal on silicon (LCoS) display optimization and application. We preliminarily demonstrate an LCoS self-calibration technique, from which we can perform a complete LCoS characterization. In particular, two important characteristics of LCoS displays are retrieved by using self-addressed digital holograms. On the one hand, we determine its phase-voltage curve by using the interference pattern generated by a digital two-sectorial split-lens configuration. On the other hand, the LCoS surface profile is also determined by using a self-addressed dynamic micro-lens array pattern. Second, the implementation of microparticle manipulation through optical traps created by an LCoS display is demonstrated. Finally, an LCoS display based inline (IL) holographic imaging system is described. By using the LCoS display to implement a double-sideband filter configuration, this inline architecture demonstrates the advantage of obtaining dynamic holographic imaging of microparticles independently of their spatial positions by avoiding the non-desired conjugate images.