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Title: Temperature-dependent modulated reflectance of InAs/InGaAs/GaAs quantum dots-in-a-well infrared photodetectors

We present a photoreflectance (PR) study of multi-layer InAs quantum dot (QD) photodetector structures, incorporating InGaAs overgrown layers and positioned asymmetrically within GaAs/AlAs quantum wells (QWs). The influence of the back-surface reflections on the QD PR spectra is explained and a temperature-dependent photomodulation mechanism is discussed. The optical interband transitions originating from the QD/QW ground- and excited-states are revealed and their temperature behaviour in the range of 3–300 K is established. In particular, we estimated the activation energy (∼320 meV) of exciton thermal escape from QD to QW bound-states at high temperatures. Furthermore, from the obtained Varshni parameters, a strain-driven partial decomposition of the InGaAs cap layer is determined.
Authors:
; ; ; ; ;  [1] ; ;  [2]
  1. Semiconductor Physics Institute, Center for Physical Sciences and Technology, A. Goštauto 11, LT-01108 Vilnius (Lithuania)
  2. School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)
Publication Date:
OSTI Identifier:
22402843
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 14; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACTIVATION ENERGY; ALUMINIUM ARSENIDES; BOUND STATE; DECOMPOSITION; ENERGY-LEVEL TRANSITIONS; EXCITED STATES; GALLIUM ARSENIDES; INDIUM ARSENIDES; LAYERS; PHOTODETECTORS; QUANTUM DOTS; QUANTUM WELLS; REFLECTION; SPECTRAL REFLECTANCE; STRAINS; TEMPERATURE DEPENDENCE