No abstract

Articles you may be interested inEnergy level(s) of the dissociation product of the 1.014eV photoluminescence copper center in n-type silicon determined by photoluminescence and deep-level transient spectroscopy

No abstract

This work presents a cost-effective technology for the formation of nanostructured semiconductor materials for tunable light emitting devices. CdS and ZnS semiconducting colloid nanoparticles coated with organic shell, containing either SO 3 or NH 3 + groups, were deposited as thin films using the technique of electrostatic self-assembly. The films produced were characterized with UV-vis spectroscopy, spectroscopic ellipsometry, and AFM. UV-vis spectra show a substantial blue shift of the main absorption band of both CdS and ZnS containing films with respect to the bulk materials, due to the phenomenon of quantum confinement. The nanoparticles' radius of 1.8 nm, evaluated from the spectral shift, corresponds well to the film thickness obtained by ellipsometry. AFM shows the formation of larger aggregates of nanoparticles on solid surfaces.

No abstract

No abstract

A combination of high resolution Laplace deep level transient spectroscopy (LDLTS) and direct capture cross-section measurements has been used to investigate whether deep electronic states related to interstitial-type defects introduced by ion implantation originated from point or extended defects, prior to any annealing. n-type silicon was implanted with doses of 1×109 cm−2 of silicon, germanium, or erbium, and comparison was made with proton- and electron-irradiated material. When measured by LDLTS at 225 K, the region of the implant thought to contain mostly vacancy-type defects exhibited a complex spectrum with five closely spaced defect-related energy levels, with energies close to EC-400 meV. The region nearer the tail of the implant, which should be dominated by interstitial-type defects, exhibited a simpler LDLTS spectrum with three closely spaced levels being recorded, again with energies centered on EC-400 meV. Annealing at 180 °C did not completely remove any of the defect peaks, suggesting that the energy levels were not due to the simple vacancy-phosphorus center. Direct electron capture cross-section measurements revealed that the defects in the tail of the implanted volume, prior to any annealing, were not simple point defects, as they exhibited nonexponential capture properties. This is attributed to the presence of extended defects in this region. By contrast, defects with the same activation energy in proton- and electron-irradiated silicon exhibited point-defect-like exponential capture.

Photoreflectance (PR) has been used for the first time for the measurement of the fundamental energy gaps of a narrow gap semiconductor (InAs) and demonstrated to be capable of determining both the bandgap and the spin-orbit split-off energy. The measurements reported in this paper give a value for the spin split-off energy for p-type InAs as 367 ± 2 meV. The assignment of the feature to the spin split-off band is supported by the observation that this value is found to be independent of temperature.