Aluminum-free strained-layer lasers emitting at 1.14 μm on low-composition InGaAs:n substrates by metalorganic chemical vapor deposition
Broad-area (W=150 /spl mu/m) single-quantum-well (SQW) lasers have been successfully fabricated on n-type In/sub 0.03/Ga/sub 0.97/As substrates without incorporating aluminum-containing alloys. The strained-layer InGaP-GaAs-InGaAs heterostructure was grown by atmospheric pressure metalorganic chemical vapor deposition. Due to both the increased substrate lattice constant and the partial strain compensation supplied by the tensile-strained GaAs optical guiding layers, a peak emission wavelength of 1.1403 /spl mu/m is obtained for a 1-mm cavity length.
Highly Strained InGaAs Quantum Well with GaAs Strain Compensating Layer on InGaAs Ternary Substrate for 1.3 μm Laser
We have developed highly strained InGaAs quantum wells (QWs) with a 1.3 μm-band emission on a low indium content InGaAs ternary substrate using low temperature metal-organic vapor phase epitaxy (MOVPE). The indium content of the substrate is 0.1, and this has the advantage of providing good thermal conductivity and good crystal quality. In this study, we newly introduced a binary GaAs barrier layer for strain compensation. We performed photoluminescence (PL) and transmission electron microscope (TEM) measurements to confirm that the crystal quality had improved. We realized a broad area laser with GaAs strain compensation that achieved low threshold current operation.
A Study on Technology Embedded English Classes Using QR Codes
The development of information and technology has brought plenty of changes to the educational environment. The prevalence of smart phones is particularly playing a huge role in shaping learning methods. Smart phones provide the opportunity to scan QR codes, which can greatly ease access to information. Due to a high recognition speed, recognition rate, and restoration rate, they can be useful tools for English teachers to use in their class. In this study, we suggest using QR codes for writing and picture descriptions. Based on this study, more research should invest in Technology Embedded English teaching models to create better English classes for students.