Two dimensional (2D) arrays of noble metal nanoparticles are widely used in the sensing of nanoscale biological and chemical events. Research in this area has sparked considerable interest in many fields owing to the novel optical properties, e.g., the localized surface plasmon resonance, of these metallic nanoarrays. In this paper, we report successes in fabricating 2D arrays of gold nano-islands using nanosphere lithography. The reproducibility and the effectiveness of the nano-patterning method are tested by means of spin coating and capillary force deposition. We found that the capillary force deposition method was more effective for nanospheres with diameters greater than 600 nm, whereas the spin coating method works better for nanospheres with diameters less than 600 nm. The optimal deposition parameters for both methods were reported, showing about 80% reproducibility. In addition, we characterize gold nano-island arrays both geometrically with AFM as well as optically with UV-VIS spectrometry. The AFM images revealed that the obtained nano-arrays formed a hexagonal pattern of truncated tetrahedron nano-islands. The experimental and theoretical values of the geometric parameters were compared. The 2D gold nano-arrays showed strong LSPR in the absorption spectra. As the nano-islands increased in size, the LSPR absorption bands became red-shifted. Linear dependence of the plasmon absorption maximum on the size of the gold nano-islands was identified through the increment in the plasmon absorption maximum rate for a one nanometer increase in the characteristic length of the nano-islands. We found that the 2D gold nano-arrays showed nearly seven-fold higher sensitivity of the absorption spectrum to the size of the nano-islands as compared to colloidal gold nano-particles.

Microelectromechanical systems (MEMS)-fabricated suspended devices were used to measure the in-plane electrical conductivity, Seebeck coefficient, and thermal conductivity of 304 nm and 516 nm thick InGaAlAs films with 0.3% ErAs nanoparticle inclusions by volume. The suspended device allows comprehensive thermoelectric property measurements from a single thin film or nanowire sample. Both thin film samples have identical material compositions and the sole difference is in the sample thickness. The measured Seebeck coefficient, electrical conductivity, and thermal conductivity were all larger in magnitude for the thicker sample. While the relative change in values was dependent on the temperature, the thermal conductivity demonstrated the largest decrease for the thinner sample in the measurement temperature range of 325 K to 425 K. This could be a result of the increased phonon scattering due to the surface defects and included ErAs nanoparticles. Similar to the results from other material systems, the combination of the measured data resulted in higher values of the thermoelectric figure of merit (ZT) for the thinner sample; this result supports the theory that the reduced dimensionality, such as in twodimensional thin films or one-dimensional nanowires, can enhance the thermoelectric figure of merit compared with bulk threedimensional materials. The results strengthen and provide a possible direction in locating and optimizing thermoelectric materials for energy applications.