A new approach for determination of free carriers lifetime and density of localised states in disordered semiconductors

Hocine Belgacem (Lead / Corresponding author), Stephen Reynolds

Research output: Contribution to journalArticle

Abstract

A new method for measuring the free carriers lifetime (Tr) and the density of localised states (DOS) in amorphous semiconductors is described. The method is based on the analysis of transient photoconductivity (TPC) data using Laplace transform technique. This technique involves Laplace transform of TPC data, it is a simple analysis of the solution of the basic linearised multiple trapping equations for free and trapped electrons. It is demonstrated by application to simulated and experimental TPC data measured on a typical disordered semiconductor, the hydrogenated amorphous silicon (a-Si:H). An introduced Tr in the computing of the TPC using an arbitrarily proposed DOS model is recovered with high accuracy. For the experimental case, the determination of the exact DOS and the estimated Tr from the experimental TPC data allow to reconstruct accurately this last. The performance and limitations of the technique are studied by means of computer simulations. Limitations are essentially the low temperatures of measurement of TPC when the recombination phenomenon is not observed at short times.
Original languageEnglish
Pages (from-to)131-147
Number of pages17
JournalPhilosophical Magazine
Volume99
Issue number2
Early online date15 Oct 2018
DOIs
Publication statusPublished - 17 Jan 2019

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Carrier lifetime
Photoconductivity
Carrier concentration
Semiconductor materials
Laplace transforms
Amorphous semiconductors
Amorphous silicon
Electrons
Computer simulation

Keywords

  • DOS
  • Laplace transform
  • recombination lifetime
  • Transient photocurrent

Cite this

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title = "A new approach for determination of free carriers lifetime and density of localised states in disordered semiconductors",
abstract = "A new method for measuring the free carriers lifetime (Tr) and the density of localised states (DOS) in amorphous semiconductors is described. The method is based on the analysis of transient photoconductivity (TPC) data using Laplace transform technique. This technique involves Laplace transform of TPC data, it is a simple analysis of the solution of the basic linearised multiple trapping equations for free and trapped electrons. It is demonstrated by application to simulated and experimental TPC data measured on a typical disordered semiconductor, the hydrogenated amorphous silicon (a-Si:H). An introduced Tr in the computing of the TPC using an arbitrarily proposed DOS model is recovered with high accuracy. For the experimental case, the determination of the exact DOS and the estimated Tr from the experimental TPC data allow to reconstruct accurately this last. The performance and limitations of the technique are studied by means of computer simulations. Limitations are essentially the low temperatures of measurement of TPC when the recombination phenomenon is not observed at short times.",
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A new approach for determination of free carriers lifetime and density of localised states in disordered semiconductors. / Belgacem, Hocine (Lead / Corresponding author); Reynolds, Stephen.

In: Philosophical Magazine, Vol. 99, No. 2, 17.01.2019, p. 131-147.

Research output: Contribution to journalArticle

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AU - Belgacem, Hocine

AU - Reynolds, Stephen

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