Dietrich R. T. Zahn

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We mechanically exfoliate mono- and few-layers of the transition metal dichalcogenides molybdenum disulfide, molybdenum diselenide, and tungsten diselenide. The exact number of layers is unambiguously determined by atomic force microscopy and high-resolution Raman spectroscopy. Strong photoluminescence emission is caused by the transition from an indirect(More)
The optical and electrical properties of terbium(III) bis(phthalocyanine) (TbPc2) films on cobalt substrates were studied using variable angle spectroscopic ellipsometry (VASE) and current sensing atomic force microscopy (cs-AFM). Thin films of TbPc2 with a thickness between 18 nm and 87 nm were prepared by organic molecular beam deposition onto a cobalt(More)
We present the results of a Raman study of optical phonons in CuS nanocrystals (NCs) with a low areal density fabricated through the Langmuir-Blodgett technology on nanopatterned Au nanocluster arrays using a combination of surface- and interference-enhanced Raman scattering (SERS and IERS, respectively). Micro-Raman spectra of one monolayer of CuS NCs(More)
The adsorption of lutetium(III) bis-phthalocyanine (LuPc(2)) on Ag(111) was investigated using scanning tunneling microscopy and spectroscopy (STM/STS). A comprehensive study was carried out toward understanding the driving mechanism responsible for the formation of the first and second monolayers (MLs). In both MLs, the adsorbed molecules are found to(More)
Hafnium silicate films with pure HfO2 and SiO2 samples as references were fabricated by atomic layer deposition (ALD) in this work. The optical properties of the films as a function of the film composition were measured by vacuum ultraviolet (VUV) ellipsometer in the energy range of 0.6 to 8.5 eV, and they were investigated systematically based on the(More)
Nanomaterials have the remarkable characteristic of displaying physical properties different from their bulk counterparts. An additional degree of complexity and functionality arises when oxide nanoparticles interact with metallic nanostructures. In this context the Raman spectra due to plasmonic enhancement of iron oxide nanocrystals are here reported(More)
The optical constants together with the magneto-optical Voigt constants of several phthalocyanine (Pc) and methoxy functionalized tetraphenylporphyrin (TMPP) thin films prepared on silicon substrates are presented. The materials investigated are MePc with Me = Fe, Co, Ni, Cu, Zn and MeTMPP with Me = Cu, Ni. We also compared our results to the metal-free(More)
Ni nanoparticles with a size distribution from 2 to 6 nm, embedded in various organic matrices, were fabricated in ultrahigh vacuum. For this purpose metal free and Ni phthalocyanine, fullerene C(60), and pentacene were coevaporated with Ni. When coevaporated, Ni and H(2)Pc react, leading to the formation of NiPc and Ni nanoparticles. The molecular(More)
The detection and control of the molecular growth mode is a key prerequisite for fabricating opto-electronic devices. In this work we present the magneto-optical Kerr effect (MOKE) spectroscopy to be a highly sensitive method for the detection of the molecular orientation. On the example of metal free phthalocyanine (H(2)Pc) in thin films, it will be shown(More)