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Volumn 6, Issue 5, 2006, Pages 948-952

Quantitative measurement of the electron and hole mobility-lifetime products in semiconductor nanowires

Author keywords

[No Author keywords available]

Indexed keywords

PHOTOCURRENT MAPPING; SCANNING PHOTOCURRENT MICROSCOPY; SEMICONDUCTOR NANOSTRUCTURES; SPATIAL PROFILES;

EID: 33744811719     PISSN: 15306984     EISSN: None     Source Type: Journal    
DOI: 10.1021/nl052576y     Document Type: Article
Times cited : (90)

References (40)
  • 23
    • 33744801665 scopus 로고    scopus 로고
    • note
    • The resistivities of ion bombarded nanowires, in contrast, were typically 0.1-1 Ω·cm and n-type as determined by the gate response.
  • 24
    • 33744780415 scopus 로고    scopus 로고
    • note
    • For injection points away from the maximum, initially unequal currents produce charge accumulation that brings the entire device into equilibrium. Note that the present analysis for resistive material is very different from that of minority carrier photoconduction at low injection. In the present case, the excess carrier concentration is much larger than the equilibrium electron concentration, leading to pure hole and electron currents at respective electrodes. In the minority carrier low injection limit, carriers do not need to reach the electrodes to contribute to the photoconductivity.
  • 25
    • 33744782033 scopus 로고    scopus 로고
    • note
    • Another possibility is that the change in the band bending (and thus potential barriers) adjacent to the contacts might increasingly hinder the collection of holes with increasing bias. However, the linear current-voltage characteristics under uniform illumination suggest that the contact effects are negligible in the carrier collection process.
  • 26
    • 33744814600 scopus 로고    scopus 로고
    • note
    • Velocity saturation is also excluded because photocurrent versus voltage curves do not saturate.
  • 27
    • 33744829725 scopus 로고    scopus 로고
    • note
    • For pure drift, the corresponding length would be L = μετ, where ε is the electric field.
  • 29
    • 33744819425 scopus 로고    scopus 로고
    • note
    • The photogenerated carriers in the devices we measured do not move as far because the carrier transport is dominated by diffusion, not drift, outside the generation region. For devices under uniform illumination, both drift and diffusion will occur throughout the device.
  • 32
    • 33744814892 scopus 로고    scopus 로고
    • note
    • For comparison, typical radiative lifetimes in bulk CdS are from 1.4 ns (ref 30) to 4 ns (ref 31). Near band-edge luminescence was studied with femtosecond laser excitation and detected with a fast micro-channel plate phototube.
  • 33
    • 33744824887 scopus 로고    scopus 로고
    • note
    • The diffusion length depends on the recombination rate, which can be influenced by the bias, however.
  • 34
    • 33744807967 scopus 로고    scopus 로고
    • note
    • It is important to note that, in contrast to carbon nanotude devices studied with SPCM, we are asserting that the depletion region lies underneath the contact and does not extend significantly into the nanowire for the bias ranges studied.
  • 35
    • 33744810296 scopus 로고    scopus 로고
    • note
    • This diffusion length is consistent with the spatial profile of the photocurrent from the NSPM study on Schottky devices in ref 19. Using the higher resolution of NSPM compared to SPCM with a confocal microscope, we determine a minority carrier diffusion length of ∼110 nm.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.