Epitaxial growth of quantum dots on InP for device applications operating at the 1.55 μm wavelength range

Elizaveta Semenova, Irina Kulkova, Shima Kadkhodazadeh, Daniele Barettin, Oleksii Kopylov, Alberto Cagliani, Kristoffer Almdal, Morten Willatzen, Kresten Yvind

Research output: Contribution to journalConference articleResearchpeer-review

Abstract

The development of epitaxial technology for the fabrication of quantum dot (QD) gain material operating in the 1.55 μm wavelength range is a key requirement for the evolvement of telecommunication. High performance QD material demonstrated on GaAs only covers the wavelength region 1-1.35 μm. In order to extract the QD benefits for the longer telecommunication wavelength range the technology of QD fabrication should be developed for InP based materials. In our work, we take advantage of both QD fabrication methods Stranski-Krastanow (SK) and selective area growth (SAG) employing block copolymer lithography. Due to the lower lattice mismatch of InAs/InP compared to InAs/GaAs, InP based QDs have a larger diameter and are shallower compared to GaAs based dots. This shape causes low carrier localization and small energy level separation which leads to a high threshold current, high temperature dependence, and low laser quantum efficiency. Here, we demonstrate that with tailored growth conditions, which suppress surface migration of adatoms during the SK QD formation, much smaller base diameter (13.6nm versus 23nm) and an improved aspect ratio are achieved. In order to gain advantage of non-strain dependent QD formation, we have developed SAG, for which the growth occurs only in the nano-openings of a mask covering the wafer surface. In this case, a wide range of QD composition can be chosen. This method yields high purity material and provides significant freedom for reducing the aspect ratio of QDs with the possibility to approach an ideal QD shape.
Original languageEnglish
Article number899606
JournalProceedings of SPIE, the International Society for Optical Engineering
Volume8996
Number of pages9
ISSN0277-786X
DOIs
Publication statusPublished - 2014
EventSPIE Photonics West : Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling XI - San Francisco, California, United States
Duration: 1 Feb 20146 Feb 2014

Conference

ConferenceSPIE Photonics West : Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling XI
CountryUnited States
CitySan Francisco, California
Period01/02/201406/02/2014

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