Interdiffused InGaAsP Quantum Dots Lasers on GaAs by Metal Organic Chemical Vapor Deposition
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0891-EE02-05.1
Interdiffused InGaAsP Quantum Dots Lasers on GaAs by Metal Organic Chemical Vapor Deposition Ronald A. Arif 1, Nam-Heon Kim2, Luke J. Mawst2, and Nelson Tansu1 1. Center for Optical Technologies, Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA 18015 2. Reed Center for Photonics, Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI 53706 ABSTRACT
Self-assembled InGaAs quantum dots (QD) grown by metal organic chemical vapor deposition (MOCVD) have a natural peak emission wavelength around 1150-1200-nm due to its specific composition, shapes, and sizes. In this work, a new method to engineer the emission wavelength capability of MOCVD-grown In0.5Ga0.5As QD on GaAs to ~1000-nm by utilizing interdiffused InGaAsP QD has been demonstrated. Incorporation of phosphorus species from the GaAsP barriers into the MOCVD-grown self-assembled In0.5Ga0.5As QD was achieved by interdiffusion process. Reasonably low threshold characteristics of ~ 200-280 A/cm2 were obtained for interdiffused InGaAsP QD lasers emitting at 1040-nm, which corresponds to blue-shift of ~ 85-90-nm in comparison to that of unannealed InGaAs QD laser. INTRODUCTION In recent years, InGaAs quantum dots (QD) have been intensively studied as one of the promising gain media for optoelectronics device applications such as edge-emitting diode lasers and vertical cavity surface emitting lasers (VCSELs) [1]. The advantages of zero-dimensional QD over two-dimensional quantum well (QW) gain media can be attributed to its reduced density of states and its sharp atomic-state like transition. Several characteristics of quantum dot gain media that benefit high power laser applications are: 1) low transparency current density potentially leads to low threshold current density and high power conversion efficiency, 2) high T0 value will be beneficial for high temperature operation, 3) the high In-content in the InGaAs QD is useful in suppressing dark line defect propagation, thus leading to improved reliability in high power laser, and 4) the absence of filamentation in QD lasers. Quantum dot lasers based on InGaAs QD gain media have been realized by molecular beam epitaxy (MBE) technology, with wavelength span from 980-nm up to 1460-nm [2-5]. High performance 980-nm MBE-grown InGaAs QD lasers have also been demonstrated up to 6.3 W at 15 0C. In contrast to that, high-performance self-assembled InGaAs QD lasers grown by metalorganic chemical vapor depositon (MOCVD) have only been demonstrated mainly in the 1150-1200 nm regime [6, 7]. The limitation of the emission wavelength observed in MOCVD-grown InGaAs QD is mainly due to the specific shapes, sizes, and size distribution that the dots assume during the epitaxy [8]. In this work, we present an approach to achieve MOCVD-grown self-assembled InGaAs QD lasers emitting at 1-µm by utilizing a P-based interdiffusion technique into the QD, resulting in interdiffused InGaAsP QD. As shown in figure 1, interdiffused InGaAsP QD lasers can be
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