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Title: Observation of room temperature optical absorption in InP/GaAs type-II ultrathin quantum wells and quantum dots

Room temperature optical absorption process is observed in ultrathin quantum wells (QWs) and quantum dots (QDs) of InP/GaAs type-II band alignment system using surface photovoltage spectroscopy technique, where no measurable photoluminescence signal is available. Clear signature of absorption edge in the sub band gap region of GaAs barrier layer is observed for the ultrathin QWs and QDs, which red shifts with the amount of deposited InP material. Movement of photogenerated holes towards the sample surface is proposed to be the main mechanism for the generation of surface photovoltage in type-II ultrathin QWs and QDs. QDs of smaller size are found to be free from the dislocations as confirmed by the high resolution transmission electron microscopy images.
Authors:
; ; ; ; ; ; ;  [1]
  1. Raja Ramanna Centre for Advanced Technology, Indore-452013, Madhya Pradesh (India)
Publication Date:
OSTI Identifier:
22304167
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; DEPLETION LAYER; DISLOCATIONS; GALLIUM ARSENIDES; INDIUM PHOSPHIDES; PHOTOLUMINESCENCE; QUANTUM DOTS; QUANTUM WELLS; RED SHIFT; RESOLUTION; SPECTROSCOPY; SURFACES; TEMPERATURE RANGE 0273-0400 K; TRANSMISSION ELECTRON MICROSCOPY