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Title: Intrinsic carrier multiplication efficiency in bulk Si crystals evaluated by optical-pump/terahertz-probe spectroscopy

We estimated the carrier multiplication efficiency in the most common solar-cell material, Si, by using optical-pump/terahertz-probe spectroscopy. Through close analysis of time-resolved data, we extracted the exact number of photoexcited carriers from the sheet carrier density 10 ps after photoexcitation, excluding the influences of spatial diffusion and surface recombination in the time domain. For incident photon energies greater than 4.0‚ÄČeV, we observed enhanced internal quantum efficiency due to carrier multiplication. The evaluated value of internal quantum efficiency agrees well with the results of photocurrent measurements. This optical method allows us to estimate the carrier multiplication and surface recombination of carriers quantitatively, which are crucial for the design of the solar cells.
Authors:
; ;  [1] ;  [1] ;  [2] ;  [3]
  1. Graduate School of Engineering Science, Osaka University, Osaka 560-8531 (Japan)
  2. (Japan)
  3. Institute for Chemical Research, Kyoto University, Kyoto 611-0011 (Japan)
Publication Date:
OSTI Identifier:
22395448
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 23; 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 SPECTROSCOPY; CARRIER DENSITY; CHARGE CARRIERS; CRYSTALS; DIFFUSION; EV RANGE; PHOTOCURRENTS; PHOTONS; PROBES; QUANTUM EFFICIENCY; RECOMBINATION; SHEETS; SILICON; SOLAR CELLS; SURFACES; TIME RESOLUTION