We present a new class of micro lasers based on nanoporous molecular sieve host-guest systems. Organic dye guest molecules of 1-ethyl-4-[4-( p-dimethylaminophenyl)-1,3-butadienyl]-pyridinium Perchlorat were inserted into the 0.73-nm-wide channel pores of a zeolite AlPO₄-5 host. The zeolitic microcrystal compounds were hydrothermally synthesized according to a particular host-guest chemical process. The dye molecules are found not only to be aligned along the host channel axis, but to be oriented as well. Single mode laser emission at 687nm was obtained from a whispering gallery mode oscillating in a 8-μm-diameter monolithic microresonator, in which the field is confined by total internal reflection at the natural hexagonal boundaries inside the zeolitic microcrystals

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Transmission electron microscopy, in particular selected area electron diffraction, was used to investigate the orientational relationship of Al, Ag, Cu, Mn, Mo, Ni, Pd, Ru, Re, and Zn deposited via physical vapor deposition on MoS 2 at room temperature. Past work has shown that a few facecentered cubic (FCC) metals (Ag, Au, Pb, Pd, and Pt) could be deposited epitaxially on MoS 2 . However, we found that additional FCC metals (Al and Cu) could be deposited epitaxially at room temperature on MoS 2 with the orientational relationship M(111)∥MoS 2 (0001) and M[22̅ 0]∥MoS 2 [112̅ 0], while a hexagonally close-packed (HCP) metal Zn was epitaxial on MoS 2 with a M(0001)∥MoS 2 (0001) and M[112̅ 0]∥MoS 2 [112̅ 0] relationship. However, the FCC metal Ni, body-centered cubic metal Mo, and HCP metals Re and Ru were not epitaxial on deposition or even after annealing at 673 K for 4 h. By comparing the results with both physical constants and modeling of the metal/MoS 2 systems, we observed that metals with a close-packed plane with six-fold symmetry, a high homologous temperature, and a low barrier to surface diffusion on MoS 2 are more likely to grow epitaxially at room temperature on MoS 2 .

Silver contacts to few-layer (5 to 14 layers thick) MoS2 have been studied before and after annealing. Annealing was found to be critical for reducing the contact resistance but did not degrade the operation of field-effect transistors that are part of the test structure. The contact resistance for the as-deposited samples was in the range of 0.8–3.5 kΩ μm. On the other hand, the contact resistance was reduced to 0.2–0.7 kΩ μm, evaluated at a constant sheet resistance of 32 kΩ/□, after annealing at 250 or 300 °C. The reduced contact resistance is attributed to diffusion of Ag into the MoS2 and doping, as supported by further electrical characterization of the contacts and devices.