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Title: Role of the wetting layer in the enhanced responsivity of InAs/GaAsSb quantum dot infrared photodetectors

InAs/GaAs{sub 1−x}Sb{sub x} Quantum Dot (QD) infrared photodetectors are analyzed by photocurrent spectroscopy. We observe that the integrated responsivity of the devices is improved with the increasing Sb mole fraction in the capping layer, up to 4.2 times for x = 17%. Since the QD layers are not vertically aligned, the vertical transport of the carriers photogenerated within the QDs takes place mainly through the bulk material and the wetting layer of the additional QD regions. The lower thickness of the wetting layer for high Sb contents results in a reduced capture probability of the photocarriers, thus increasing the photoconductive gain and hence, the responsivity of the device. The growth of not vertically aligned consecutive QD layers with a thinner wetting layer opens a possibility to improve the performance of quantum dot infrared photodetectors.
Authors:
; ; ;  [1] ;  [2]
  1. Instituto de Sistemas Optoelectrónicos y Microtecnología y Dept. Ingeniería Electrónica, Universidad Politécnica de Madrid, ETSI de Telecomunicación, Avda. Complutense 30, 28040 Madrid (Spain)
  2. IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid (Spain)
Publication Date:
OSTI Identifier:
22483135
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 1; 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; AUGMENTATION; CARRIERS; EQUIPMENT; GAIN; GALLIUM ARSENIDES; INDIUM ARSENIDES; LAYERS; PERFORMANCE; PHOTODETECTORS; PROBABILITY; QUANTUM DOTS; SPECTROSCOPY