相关论文: Phonon-assisted optical absorption of SiC polytype…
We develop a first-principles theory of phonon-assisted optical absorption in semiconductors and insulators which incorporates the temperature dependence of the electronic structure. We show that the Hall-Bardeen-Blatt theory of indirect…
The phonon-assisted interband optical absorption spectrum of silicon is calculated at the quasiparticle level entirely from first principles. We make use of the Wannier interpolation formalism to determine the quasiparticle energies, as…
Silicon carbide (SiC) is a wide band gap semiconductor with a variety of industrial applications. Among its many useful properties is its high thermal conductivity, which makes it advantageous for thermal management applications. In this…
Laboratory measurements of unpolarized and polarized absorption spectra of various samples and crystal stuctures of silicon carbide (SiC) are presented from 1200--35,000 cm$^{-1}$ ($\lambda \sim$ 8--0.28 $\mu$m) and used to improve the…
Silicon nanocrystals (SiNCs) have been under active investigation in the last decades and have been considered as a promising candidate for many optoelectronic applications including highly-efficient solar cells. Some of the fundamental…
Ab initio based accurate simulation of phonon-assisted optical spectra of semiconductors at finite temperatures remains a formidable challenge, as it requires large supercells for phonon sampling and computationally expensive high-accuracy…
Discovery of high-performance materials remains one of the most active areas in photovoltaics (PV) research. Indirect band gap materials form the largest part of the semiconductor chemical space, but predicting their suitability for PV…
Degenerate two-photon indirect absorption in silicon is an important limiting effect on the use of silicon structures for all-optical information processing at telecommunication wavelengths. We perform a full band structure calculation to…
Recently, Zacharias et al [Phys. Rev. Lett. 115, 177401 (2015)] developed a new ab initio theory of temperature-dependent optical absorption spectra and band gaps in semiconductors and insulators. In that work the zero-point renormalization…
The optical properties of silicon can be greatly tuned by applying strain and opening new perspectives, particularly in applications where infrared is key. In this work, we use a recent model for the indirect light absorption of silicon and…
Phonon assisted photoluminescence provides a direct window into exciton phonon interactions in low dimensional semiconductors. Using fully ab initio many body perturbation theory, including finite momentum Bethe Salpeter calculations, we…
The basic theoretical foundation for the modelling of phonon assisted absorption spectra in direct bandgap semiconductors, introduced by Elliott 60 years ago using second order perturbation theory, results in a square root shaped dependency…
We investigate the temperature effect on the electronic band structure and optical absorption property of wide-band-gap ternary nitride MgSiN$_2$ using first-principles calculations. We find that electron-phonon coupling leads to a sizable…
We present a theory of electronic excitation energies and optical absorption spectra which incorporates energy-level renormalization and phonon-assisted optical absorption within a unified framework. Using time-independent perturbation…
Two-photon absorption in indirect gap semiconductors is an frequently encountered, but not well-understood phenomenon. To address this, the Real Density Matrix Approach is applied to describe two-photon absorption in silicon through the…
Future laser-interferometric gravitational wave detectors (GWDs) will potentially employ test mass mirrors from crystalline silicon and a laser wavelength of $1550\,\rm{nm}$, which corresponds to a photon energy below the silicon bandgap.…
We have performed first principles electron-correlated calculations employing large basis sets to optimize the geometries, and to compute linear optical absorption spectra of various low-lying conformers of silicon hydrides:…
In this paper, we analyse the optical absorption in porous silicon . This is the first attempt to explicitly demonstrate that it is not possible to extract the band gap of such low dimensional nanostructures like porous silicon from a Tauc…
In indirect band gap materials, phonon-assisted processes are key mechanisms for photoluminescence (PL). Using a first-principles many-body approach, we systematically investigate the phonon-assisted PL in bilayer MoS$_2$ and its dependence…
In this paper, we report on the optical absorption in porous silicon. We model the absorption process assuming that porous silicon is a pseudo 1D material system having a distribution of band gaps. We show that in order to explain the…