This paper shows how bandgap EEL spectra are commonly processed either by deconvolution or subtraction methods in an attempt to remove effects arising from the finite width and long tail of the zero loss peak. This paper will compare the two main methods, and show that the deconvolution method is significantly more reliable and free of user-interpretation or artefacts. We first consider how the...

InPBi thin films have been grown on InP by gas source molecular beam epitaxy. A maximum Bi composition of 2.4% is determined by Rutherford backscattering spectrometry. X-ray diffraction measurements show good structural quality for Bi composition up to 1.4% and a partially relaxed structure for higher Bi contents. The bandgap was measured by optical absorption, and the bandgap reduction caused ...

Bandgap engineering of single-crystalline alloy Cd(x)Zn(1-x)Te (0 ≤ x ≤ 1) nanowires is achieved successfully through control of growth temperature and a two zone source system in a vapor-liquid-solid process. Extensive characterization using electron microscopy, Raman spectroscopy and photoluminescence shows highly crystalline alloy nanowires with precise tuning of the bandgap. It is well know...

Photodetectors based on quasi-metallic carbon nanotubes exhibit unique optoelectronic properties. Due to their small bandgap, photocurrent generation is possible at room temperature. The origin of this photocurrent is investigated to determine the underlying mechanism, which can be photothermoelectric effect or photovoltaic effect, depending on the bandgap magnitude of the quasi-metallic nanotube.

This thesis investigates packaging effects on precision bandgap voltage references used in LTC switching regulators. Packaging stress causes a mean offset and room temperature distribution widening of the bandgap reference output voltage, as well as inconsistent temperature characteristics. Bandgap references with and without a proprietary stress-relief mechanism were compared to determine the ...

While polymer light-emitting diodes are currently finding commercial applications in displays and lighting, the development of low bandgap polymers emitting in the infrared has received much less attention in spite of potential applications for instance in the field of communication technologies. We report here a light emission at 1 eV from a low bandgap polymer made of an alternation of dialko...

Interference lithography for the fabrication of photonic crystals is considered. A two-stage design method for realization of photonic bandgap structures with desired symmetries is developed. An optimal photonic crystal with a large bandgap is searched by adjusting some parameters while keeping some basic symmetry of the unit cell unchanged. A nonlinear programming method is then used to find t...

This article reports the X-ray diffraction-based structural characterization of the α12 multilayer structure SiGe2Si2Ge2SiGe12 [d'Avezac, Luo, Chanier & Zunger (2012 ▶). Phys. Rev. Lett.108, 027401], which is predicted to form a direct bandgap material. In particular, structural parameters of the superlattice such as thickness and composition as well as interface properties, are obtained. Moreo...

An inherent polarization sensitivity of a volume grating, in general, can be used to determine all the Stokes parameters of input beams. We demonstrate the polarization-dependent bandgap in a photonic crystal in principle at any wavelength using the finite-difference time-domain method. We show how this bandgap can be used to realize a volume-grating Stokesmeter. We also present an explicit des...

We demonstrate multiple bandgap integration on the hybrid silicon platform using quantum well intermixing. A broadband DFB laser array and a DFB-EAM array are realized on a single chip using four bandgaps defined by ion implantation enhanced disordering. The broadband laser array uses two bandgaps with 17 nm blue shift to compensate for gain roll-off while the integrated DFB-EAMs use the as-gro...