Observation of natural superlattice in AlXGa1-XAs layers grown by metalorganic vapor phase epitaxy

A. Pradhan, T. Maitra, S. Mukherjee, S. Mukherjee, A. Nayak, B. Satpati, S. Bhunia

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Atomic Cu-Pt type ordering in monolayer scale is well known in Ga0.5 In0.5 P epitaxial layers leading to change in its bandgap. Despite wide scale use of AlxGa1-xAs (0<x<0.7) in various optoelectronic devices and quantum well structures, spontaneous ordering in this system was not well studied beyond monolayer scale. In this work, we report observation of natural superlattice ordering due to compositional variation in MOVPE grown AlxGa1-xAs epitaxial layers. Clear evidence of such ordering was first noticed in the barrier layers of GaAs/Al0.3Ga0.7As quantum well structures. Further investigation on bulk epitaxial growth of AlxGa1-xAs layer with different composition (x=0.2) has also confirmed existence of such structures. We have probed the sample using high resolution Transmission Electron Microscopy coupled with x-ray rocking curve (XRC) and reflectivity (XRR) measurements. Sharp superlattice peaks around (004) substrate Bragg peak as well as around (002) forbidden peak in XRC have been observed. Similar peaks are present in XRR also. We have presented detailed analysis of X-ray diffraction data with the help of kinematical diffraction theory here. The stability of the superlattice structures has been further investigated by annealing the sample at different temperatures.

Original languageEnglish
Title of host publicationInternational Conference on Condensed Matter and Applied Physics, ICC 2015
Subtitle of host publicationProceeding of International Conference on Condensed Matter and Applied Physics
EditorsManoj Singh Shekhawat, Sudhir Bhardwaj, Bhuvneshwer Suthar
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735413757
DOIs
StatePublished - 6 May 2016
Externally publishedYes
EventInternational Conference on Condensed Matter and Applied Physics, ICC 2015 - Bikaner, India
Duration: 30 Oct 201531 Oct 2015

Publication series

NameAIP Conference Proceedings
Volume1728
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

ConferenceInternational Conference on Condensed Matter and Applied Physics, ICC 2015
Country/TerritoryIndia
CityBikaner
Period30/10/1531/10/15

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