ABSTRACT
Optical properties of the FePt-C nanocomposite thin film that was synthesized by sputtering with MgO/NiTa underlayer on glass substrate have been determined by an approach combining spectroscopic ellipsometry and transmission over the wavelength range of 380 - 1700 nm. It was observed that the refractive index is larger than the extinction coefficient, indicating that free electron absorption is not the dominant optical transition in the FePt-C thin film. Compared with FePt thin film, the FePt-C thin film has smaller optical constants, which lead to better optical performance including smaller optical spot on recording media and higher transducer efficiency for heat assisted magnetic recording.
Subject(s)
Carbon/chemistry , Information Storage and Retrieval/methods , Iron/chemistry , Membranes, Artificial , Optical Devices , Platinum/chemistry , Refractometry/instrumentation , Carbon/radiation effects , Equipment Design , Equipment Failure Analysis , Hot Temperature , Iron/radiation effects , Magnetic Fields , Platinum/radiation effectsABSTRACT
Room-temperature random lasing is achieved from an n-AlN/p-GaN heterojunction. The highly disordered n-AlN layer, which was deposited on p-GaN:Mg layer via radio frequency magnetron sputtering, acts as a scattering medium to sustain coherent optical feedback. The p-GaN:Mg layer grown on sapphire provides optical amplification to the scattered light propagating along the heterojunction. Hence, lasing peaks of line width less than 0.4 nm are emerged from the emission spectra at round 370 nm for the heterojunction under forward bias larger than 5.1 V. Lasing characteristics of the heterojunction are in agreement with the behavior of random lasers.
ABSTRACT
Visible electroluminescence (EL) with two composite bands, i.e., a violet band and a green-yellow band has been observed from Si-implanted silicon nitride thin films. By varying the intensity ratio of the two composite EL bands in terms of the injection current, strong white-color EL can be achieved at certain injection currents (e.g., ~265 mA/cm(2)). The observed transition in EL color from violet to white under different injection conditions is studied based on the understanding that the violet band is originated from silicon nitride matrix while the green-yellow band is related to the implanted Si. The Si-implanted silicon nitride thin film offers the possibility of electrically tunable white-light Si-based light emitters.
Subject(s)
Lighting/instrumentation , Luminescent Measurements/instrumentation , Membranes, Artificial , Semiconductors , Silicon Compounds/chemistry , Silicon/chemistry , Color , Electromagnetic Fields , Equipment Design , Equipment Failure AnalysisABSTRACT
The split of surface plasmon resonance of self-assembled gold nanoparticles on Si substrate is observed from the dielectric functions of the nanoparticles. The split plasmon resonances are modeled with two Lorentz oscillators: one oscillator at ~1 eV models the polarization parallel to the substrate while the other at ~2 eV represents the polarization perpendicular to the substrate. Both parallel and perpendicular resonances are red-shifted when the nanoparticle size increases. The red shifts in both resonances are explained by the image charge effect of the Si substrate.
