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Comprehensive study on molecular beam epitaxy-grown InAs sub-monolayer quantum dots with different capping combinations

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Title Comprehensive study on molecular beam epitaxy-grown InAs sub-monolayer quantum dots with different capping combinations
 
Creator SENGUPTA, S
MANDAL, A
GHADI, H
CHAKRABARTI, S
MATHUR, KL
 
Subject WELL INFRARED PHOTODETECTORS
 
Description Here the authors report a comprehensive study on InAs sub-monolayer quantum dots with different capping layers. After performing systematic optimization of InAs deposition and GaAs thickness, they grew three samples, namely A, B and C, using solid-state molecular beam epitaxy with identical architecture but different capping materials (2nm of GaAs, InGaAs-GaAs, and InAlGaAs-GaAs, respectively). Photoluminescence emission peaks due to the ground state transition from the dots were observed at 898, 917, and 867nm for samples A, B, and C, respectively. Narrow full-width half-maxima (19-32meV) of the emission peaks indicates high uniformity of dot size distribution. Using the conventional Arrhenius plot, the authors calculated the thermal activation energies from temperature-dependent photoluminescence experiment for samples A, B, and C as 49, 112, and 109meV, respectively. To complete the study, single-pixel photodetectors were fabricated from samples A, B, and C and temperature-dependent dark current variation with applied bias voltage was measured. Dark current was calculated to be in the range of 10(-5)-10(-4) A/cm(2) at a 0.5V applied bias at 77 K. The activation energies calculated from temperature-dependent dark current measurement for samples A, B, and C were 75, 160, and 155meV, respectively, and followed the trend observed in temperature-dependent photoluminescence measurements. (C) 2013 American Vacuum Society.
 
Publisher A V S AMER INST PHYSICS
 
Date 2014-10-15T08:43:03Z
2014-10-15T08:43:03Z
2013
 
Type Article
 
Identifier JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 31(3)
http://dx.doi.org/10.1116/1.4805018
http://dspace.library.iitb.ac.in/jspui/handle/100/14712
 
Language en