PbTe(In) films with variable microstructure for photodetection in IR and terahertz range

Ludmila Ryabova, Vladimir Chernichkin, Alexandr Dobrovolsky, Vladimir Kasiyan, Vasily Bel'Kov, Sergey Danilov, Zinovi Dashevsky, Sergei Ganichev, Dmitriy Khokhlov

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

2 Scopus citations

Abstract

The work deals with studies of the grain size and surface state effect on photoelectric and transport properties of PbTe(In) films in the temperature range from 4.2 K up to 200 K under irradiation of a blackbody source and terahertz laser pulses. The PbTe(In) films were deposited on insulating substrates kept at the temperatures T S equal to -120 C H 250C. AFM, SEM, Auger spectroscopy and X-ray diffraction were used to study the film microstructure. Increase of the T S value led to mean grain size growth from 60 up to 300 nm. All films had a column-like structure with the columns nearly perpendicular to the substrate plane. It is shown that microstructure of the films strongly affects the photoconductivity character in the terahertz region of the spectrum. Positive persistent photoresponse is observed at low temperatures in the polycrystalline films. For these films transport and photoelectric properties are determined by the grain volume and impurity state specifics. Nanocrystalline films have all features of non-homogeneous systems with band modulation. For these films only negative photoconductivity is observed in the whole temperature range. Possible mechanisms of the photoresponse formation are discussed.

Original languageEnglish
Title of host publicationOptical Sensing and Detection II
DOIs
StatePublished - 12 Jun 2012
EventOptical Sensing and Detection II - Brussels, Belgium
Duration: 16 Apr 201219 Apr 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8439
ISSN (Print)0277-786X

Conference

ConferenceOptical Sensing and Detection II
Country/TerritoryBelgium
CityBrussels
Period16/04/1219/04/12

Keywords

  • Doping
  • Grain size
  • Impurity states
  • Photoconductivity
  • Semiconductor

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