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Nanocomposites CoO x /SnO 2 based on tin oxide powders with different crystallinity have been prepared by wet chemical synthesis and characterized in detail by ICP-MS, XPS, EPR, XRD, HAADF-STEM imaging and EDX-STEM mapping. It was shown that cobalt is distributed differently between the bulk and surface of SnO 2 nanocrystals, which depends on the crystallinity of the SnO 2 matrix. The measurements of gas sensor properties have been carried out during exposure to CO (10 ppm), and H 2 S (2 ppm) in dry air. The decrease of sensor signal toward CO was attributed to high catalytic activity of Co 3 O 4 leading to oxidation of carbon monoxide entirely on the surface of catalyst particles. The formation of a p-CoO x /n-SnO 2 heterojunction results in high sensitivity of nanocomposites in H 2 S detection. The conductance significantly changed in the presence of H 2 S, which was attributed to the formation of metallic cobalt sulfide and removal of the pn junction.

Light sources with ultra-low energy consumption and high performance are required to realize optical interconnects for on-chip communication. Photonic crystal (PhC) nanocavity lasers are one of the most promising candidates to fill this role. In this work, we demonstrate an electrically-driven PhC nanolaser with an ultra-low threshold current of 10.2 µA emitting at 1540 nm and operated at room temperature. The lasers are InP-based bonded on Si and comprise a buried heterostructure active region and lateral p-i-n junction. The static characteristics and the thermal properties of the lasers have been characterized. The effect of disorder and p-doping absorption on the Q-factor of passive cavities was studied. We also investigate the leakage current due to the lateral p-i-n geometry by comparing the optical and electrical pumping schemes.

We present a systematic study of Zn thermal diffusion and Si ion implantation with subsequent rapid thermal annealing as the methods to fabricate lateral p-in junctions in InP membranes on silicon for use in electrically pumped in-plane nanolasers. We describe in detail optimized fabrication steps, which include MOVPE growth of InGaAs/InP epilayers, 2" InP to 4" SiO2/Si direct bonding, and several cycles of DUV lithography. Values for sheet resistance of p-InGaAs/InP and n-InP membranes are obtained, which correspond to carrier concentration levels higher than 10 18 cm-3 for both Zndiffused p-InP and Si-implanted n-InP.