Abstract: With photoresist dot arrays fabricated by a two-beam interference lithography as an etch mask, two-dimensional (2-D) hexagonal aluminum-doped zinc oxide（AZO）submicron gratings (SMG) with 160nm height (h) and different periods (P) were produced using lift-off transfer process. Results show that as P decreased to 487nm, SMG exhibited excellent antireflection properties, which reduced the average total reflectivity (Rtotal) from 11.8% of AZO thin film to 4.7% in the wavelength range of 400nm-1050nm, and promoted the total transmittance (Ttotal) significantly, especially in the long spectral range of 750nm-1050nm. On the other hand, as P increased from 487nm to 985nm, the haze parameters of reflectance (HR) or transmittance (HT) improved from 25.5% to 40.2% or from 15.1% to 36.8%, respectively. Nevertheless, P increased from 985nm to 1435nm, both Rtotal (or Ttotal) and HR (or HT) varied very slightly. Bidirectional distribution functions at normal incidence not only verified that the larger the P was, the part of diffuse reflectance (or transmittance) were much higher, but also further demonstrate the larger the P, the smaller the diffaction angle. In summary, 2-D hexagonal AZO SMG show promising antireflection effects at P less than 487nm, and show promising scattering abilities at P about 985nm.
Abstract: Porous silicon based visible light photodetectors with the characteristic structures of Al/porous silicon/Si were developed by evaporating aluminum contact onto the top surface of porous silicon films to form metal-semiconductor-metal Schottky junctions. The spongy nanostructures of the porous silicon film were characterized with the scanning electron microscopy. The current-voltage characteristics, the biased voltage dependent photocurrents and the illumination intensity dependent photocurrents were measured for the Al/porous silicon/Si visible light photodetectors. It is found that the photocurrents as large as 4 mA/cm2 can be achieved for the porous silicon based visible light photodetectors under the normal illumination of one 500 W tungsten lamp
Abstract: Abstract. Microstructural, optical and mechanical properties of oxide and fluoride films are examined. Superior optical quality, durability and environmental stability are achieved for oxides deposited by ion assist reactive ion beam sputtering and thermal evaporation. The materials and deposition techniques are discussed with regards to manufacturing of optical interference filters for near-UV – mid-IR wavelengths. High performance of thin film materials and optical filters is demonstrated.