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Optical and electrical properties of alpha-monoclinic selenium

Citation

Caywood, John Millard (1969) Optical and electrical properties of alpha-monoclinic selenium. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-09112002-170638

Abstract

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The optical absorption of [alpha]-monoclinic selenium has been measured over the range in wavelength 1.15 [micron] to 0.2775 [micron]. The data show a well defined absorption edge at 2.25 eV with further structure appearing as changes in [...] at 2.85 eV and 3.75 eV. For comparison the absorption of selenium in solutions in which it is believed to exist in the same eight-membered puckered ring as in the crystal was measured. This absorption is qualitatively different from that of the crystal.

The existence of surface barriers on [alpha]-monoclinic selenium crystals has been demonstrated. Photometric measurements indicate electron barrier heights of 1.05 eV and 1.3 eV, respectively, for Ga and Au contacts. The mobilities of holes and electrons have been measured by a time-of-flight technique to be about 0.2 [centimeters squared]/V-sec and 1.6 [centimeters squared]/V-sec, respectively, at room temperature. The hole mobility was found to be limited by traps 0.23 [plus/minus] .01 eV above the valence levels, while the electron mobility is an intrinsic mobility limited only by scattering. It was found that in the region of low carrier density (i.e. no space charge effects) the number of carriers which crossed the sample was determined by the interplay of the applied field (carrying carriers across the sample) and diffusion (carrying carriers into the metal contact where they relax). The dielectric constant, K, was determined to be 9.2 [plus/minus] .6 over the range 100 [kilohertz] to 100 [megahertz].

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Mead, Carver
Thesis Committee:
  • Unknown, Unknown
Defense Date:6 May 1969
Record Number:CaltechETD:etd-09112002-170638
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-09112002-170638
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3450
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:13 Sep 2002
Last Modified:26 Dec 2012 03:00

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