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CdO-Ga 2 O 3 alloy films (Cd 1-x Ga x O 1+δ ) over the whole composition range (x=0 to 1) were synthesized by room temperature radio frequency magnetron sputtering. We found that the intrinsic band gap of these alloys can be tuned in a wide range from 2.2 to 4.8 eV. As the Ga content increases to x>0.3 the alloy becomes entirely amorphous and the resistivity increases from 10−3 to 10−1 ohm-cm while the mobility decreases gradually from 15 (x=0.34) to 10 cm2/Vs (x=0.6). The resistivity of amorphous Cd 1-x Ga x O 1+δ films can be further controlled from 10−3 to 102 ohm-cm by oxygen doping. Moreover, alloy films grown on plastic (PEN) substrate exhibit similar electrical and optical properties. These results suggest that amorphous Cd 1-x Ga x O 1+δ alloy films can potentially be used as highly conducting transparent conductors on flexible solar cells as well as gate electrodes with a wide bandgap tunabilty for transparent/flexible devices.

We have studied the enhancement factors (EF) in Surface Enhanced Raman Scattering (SERS) substrates prepared with self assembled ZnO nanorod arrays and Au nanocrystals. The ZnO/Au composite nanoarrays present experimental EF values as high as ∼07 for detection of Rhodamine 6G (R6G) using an excitation wavelength of 633 nm. We have study the EF via numerical simulations of a single ZnO/Au composite nanorod using a FDTD algorithm. Our results indicate that the coupling between the photonic wave guiding in the ZnO nanorod and the plasmonic resonance in the Au nanocrystals plays a significant role in the observed EF and need to be considered to fully understand and optimize the development of high efficiency, reproducible, and stable SERS substrates.

We report the application of the UV-extended multichannel ellipsometer in studies of the growth and layered structure of cBN films deposited on c-Si using pulsed dc sputtering of a B/sub 4/C target with rf substrate bias.