Feasibility Of Novel Si-Based Interminiband Lasers

1998 ◽  
Vol 533 ◽  
Author(s):  
Gregory Sun ◽  
Lionel Friedman ◽  
Richard A. Soref
Keyword(s):  
Quantum Wells ◽  
Current Density ◽  
Population Inversion ◽  
Heavy Hole ◽  
Optical Gain ◽  
Laser Structure ◽  
Strained Si ◽  
Superlattice Structures ◽  
A Current

AbstractWe have designed a parallel interminiband lasing in superlattice structures of coherently strained Si0.5Ge0.5/Si quantum wells (QWs). Population inversion is achieved between the non-parabolic heavy-hole valence minibands locally in-k-space. Lasing transition is at 5.4μm. Our analysis indicates that an optical gain of 134/cm can be obtained when the laser structure is pumped with a current density of 5kA/cm2.

scholarly journals Optical Gain and Radiative Current Density in Strain Compensated GaAsP/GaAsBi/GaAsP QWs Laser Structure

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Sfina N ◽  
Jbeli A ◽  
Lazzari JL ◽  
Said M
Keyword(s):  
Current Density ◽  
Optical Gain ◽  
Laser Structure

Modulated Reflectance Spectroscopy of CdTe-Cd1−xMnxTe Multiple Quantum Wells and Superlattices Grown by Pulsed Laser Evaporation and Epitaxy

1992 ◽  
Vol 285 ◽  
Author(s):  
D. Labrie ◽  
J.J. Dubowski
Keyword(s):  
Quantum Wells ◽  
Heavy Hole ◽  
Free Exciton ◽  
Multiple Quantum Well ◽  
Pulsed Laser ◽  
Reflectance Spectroscopy ◽  
Light Hole ◽  
Laser Evaporation ◽  
Multiple Quantum ◽  
Superlattice Structures

ABSTRACTPiezoreflectance and photoreflectance spectroscopies have been used to investigate the electronic properties of CdTe-Cd1-xMnxTe (x − 0.10) multiple quantum well and superlattice structures grown by Pulsed Laser Evaporation and Epitaxy (PLEE). The structures with the CdTe well widths from 54Å to 245Å have been investigated. The spectra exhibit a series of signatures which are attributed to free exciton transitions occuring between the heavy-hole and light-hole bands and the upper electron subbands within the CdTe well layers. The spectra indicate that the PLEE grown structures are of an excellent quality typical of the best currently available material.

Design and Simulation of a Mid-Infrared Quantum Cascade Laser Based on Ge-Si Superlattices

2007 ◽  
Vol 121-123 ◽  
pp. 677-680
Author(s):  
Yan Wu Lu ◽  
Gregory Sun
Keyword(s):  
Effective Mass ◽  
Quantum Cascade Laser ◽  
Current Density ◽  
Population Inversion ◽  
Optical Gain ◽  
Light Hole ◽  
Mid Infrared ◽  
Hole Effective Mass ◽  
Quantum Cascade ◽  
Simple Quantum

This paper presents a novel valance intersubband laser based on Si-based Si-Ge superlattices grown on a relaxed Si0.5Ge0.5 buffer layer. Effective mass theory is used to calculate the inplane valence subband dispersion of Si-Ge superlattices within 6×6 Kane model. Analysis of the inplane energy dispersion shows that the light-hole effective mass is inverted at off zone center region. The laser structure can be designed with a simple quantum cascade scheme. Our calculation shows that with the electrical pump, it is possible to achieve population inversion between the two subbands at local k space where the light-hole effective mass is inverted. Optical gain of the order 100/cm can be achieved with a pumping current density 10 kA/cm2.

Analysis of Optical Gain of Strained Wurtzite InxGa1-xN/GaN Quantum Well Lasers

1997 ◽  
Vol 482 ◽  
Author(s):  
T. C. Chong ◽  
Y. C. Yeo ◽  
M. F. Li ◽  
W. J. Fan
Keyword(s):  
Quantum Wells ◽  
Mole Fraction ◽  
Current Density ◽  
Compressive Strain ◽  
Optical Gain ◽  
Numerical Approach ◽  
Threshold Current ◽  
Threshold Current Density ◽  
Analytical Approximations ◽  
Suitable Combination

AbstractThe valence subband structures, density-of-states, and optical gain of (0001) wurtzite (WZ) InxGa1-xN/GaN quantum wells (QWs) are studied using a numerical approach without analytical approximations. We used the effective-mass parameters of GaN and InN derived using the Empirical Pseudopotential Method. By varying the well width and mole fraction of In in the well material, the effects of quantum confinement and compressive strain are studied. A narrower well width and a higher In mole fraction in the well lead to TE enhancement and TM suppression of the optical gain. From the relationship between the optical gain and the radiative current density, we obtain the transparent current density for a single QW to be 200 A/cm2. Further, we analyze the InxGa1-xN/GaN/AlGaN separate confinement heterostructure multiple-QW laser structure. It is shown that a suitable combination of well width and number of QWs should be selected in optimizing the threshold current density in such MQW lasers

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

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