MOCVD Grown InGaAs/InAlAs Quantum Cascade Lasers Emitting at 7.7 μm

In this paper, we report the growth of high-quality <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>In</mi><mrow><mn>0.59</mn></mrow></msub><msu...

Full description

Saved in:
Bibliographic Details
Main Authors: Maciej Bugajski, Andrzej Kolek, Grzegorz Hałdaś, Włodzimierz Strupiński, Iwona Pasternak, Walery Kołkowski, Kamil Pierściński
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Photonics
Subjects:
Online Access:https://www.mdpi.com/2304-6732/11/12/1195
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In this paper, we report the growth of high-quality <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>In</mi><mrow><mn>0.59</mn></mrow></msub><msub><mi>Ga</mi><mrow><mn>0.41</mn></mrow></msub><mi>As</mi><mo>/</mo><msub><mi>In</mi><mrow><mn>0.37</mn></mrow></msub><msub><mi>Al</mi><mrow><mn>0.63</mn></mrow></msub><mi>As</mi></mrow></semantics></math></inline-formula> strain-balanced quantum cascade lasers (QCLs) in the low-pressure MOCVD production type multi-wafer planetary reactor addressing, in particular, quality and scaled manufacturing issues. Special attention was given to achieving the sharp interfaces (IFs), by optimizing the growth interruptions time and time of exposure of InAlAs layer to oxygen contamination in the reactor, which all result in extremely narrow IFs width, below 0.5 nm. The lasers were designed for emission at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>7.7</mn><mspace width="0.166667em"></mspace><mo>µ</mo></mrow></semantics></math></inline-formula>m. The active region was based on diagonal two-phonon resonance design with 40 cascade stages. For epitaxial process control, the High Resolution X-Ray Diffraction (HR XRD) and Transmission Electron Microscopy (TEM) were used to characterize the structural quality of the QCL samples. The grown structures were processed into mesa Fabry-Perot lasers using dry etching RIE ICP processing technology. The basic electro-optical characterization of the lasers is provided. We also present results of Green’s function modeling of QCLs and demonstrate the capability of non-equilibrium Green’s function (NEGF) approach for sophisticated, but still computationally effective simulation of laser’s characteristics. The sharpness of the grown IFs was confirmed by direct measurements of their chemical profiles and as well as the agreement between experimental and calculated wavelength obtained for the bandstructure with ideally abrupt (non-graded) IFs.
ISSN:2304-6732