Articles you may be interested inCharacterization of cubic boron nitride growth using UV-extended real-time spectroscopic ellipsometry: Effect of plasma additions and dynamic substrate bias steps Cubic boron nitride thin film deposition by unbalanced magnetron sputtering and dc pulsed substrate biasing Phase and microstructure investigations of boron nitride thin films by spectroscopic ellipsometry in the visible and infrared spectral range

Different types of electrochromic devices for thermal emittance modulation were developed in the spectral region from mid-to far-infrared ͑2-40 m͒. In all devices polycrystalline and amorphous tungsten oxide have been used as electrochromic and ion storage layer, respectively. Two types of all-solid-state devices were designed, one with a metal grid for the top and bottom electrode deposited on a highly emissive glass substrate, and another with a top metal grid electrode and a highly reflecting bottom metal electrode layer. Tantalum oxide is used as an ion conductor in both device types. The third device type consists of a polymeric ion conductor. All solid-state constituent layers were grown by either reactive or nonreactive dc or rf magnetron sputtering in a high vacuum environment. Modulation of the emittance is accomplished by reversible insertion of Li ions into polycrystalline WO 3 by applying and switching a small voltage across the structure. Spectrally dependent measured reflectance modulation of the device has been used to determine the device emissivity modulation with respect to the blackbody emissivity spectra at 300 K. Best device performance was found in both solid-state devices showing an emissivity modulation of about 20%.

All-solid-state electrochromic reflectance devices for thermal emittance modulation were designed for operation in the spectral region from mid- to far-infrared wavelengths (2–40 μm). All device constituent layers were grown by magnetron sputtering. The electrochromic (polycrystalline WO3), ion conductor (Ta2O5), and Li+ ion-storage layer (amorphous WO3), optimized for their infrared (IR) optical thicknesses, are sandwiched between a highly IR reflecting Al mirror, and a 90% IR transmissive Al grid top electrode, thereby meeting the requirements for a reversible Li+ ion insertion electrochromic device to operate within the 300 K blackbody emission range. Multicycle optical switching and emittance modulation is demonstrated. The measured change in emissivity of the device is to 20%.

Schubert, Mathias; Rheinlander, B.; Franke, E.; Neumann, H.; Tiwald, T. E.; and Woollam, John A., "Infrared optical properties of mixed-phase thin films studied by spectroscopic ellipsometry using boron nitride as an example" (1997 We present a microstructure-dependent anisotropic infrared-optical dielectric function model for mixedphase polycrystalline material from which we derive the transverse and longitudinal-optical modes observable in thin films. Infrared ellipsometry over the wavelength range from 700 to 3000 cm Ϫ1 is then used to determine the phase and microstructure of polycrystalline and multilayered hexagonal and cubic boron nitride thin films deposited by magnetron sputtering onto ͑100͒ silicon. The ellipsometric data depend on the thin-film multilayer structure, the layer-phase composition, and the average orientation of the hexagonal grain c axes. In particular, we demonstrate the existence of spectral shifts of longitudinal optical phonons as a function of microstructure, i.e., the average grain crystallographic orientation within the mixed-phase material. ͓S0163-1829͑97͒08244-1͔