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Gallium Arsenide

  1. Jul 28, 2008 #1
    I hope someone can assist me in explaining some characteristics of Gallium Arsenid.
    I am currently looking at optical temperature sensors and see that Gallium Arsenide is used as a temperature sensitive material and after researching some of this on te web i have a few questions.
    I have found out that the reason gallium arsenide is used is because it is a semiconductor with a direct band gap. The band gap is temperature sensitive in that it changes due to changes with temperature.Thus due to the change in the band gap with temperature there is a change of the absorption edge of GaAs as in it is transparent up to a certain point dependant on its band gap and then past this wavelength the light is absorbed. As i said this absorption ege shifts due to increased temperature and thus this phenomenon can be measured optically.

    However this is just the basics and i cannot seem to find anymore information on it. Such as is it a pure undoped gallium arsenide crystal or chip used or a doped GaAs chip and if so is it n or p type doped, or is it an alloyed GaAs chip such as Alluminium gallium arsenide and if so what is the alooy ratio????

    Also there is a question of what size of a crystal is needed and how the band gap can be calculated to get a certain temperature range for the GaAs semiconductor crystal which i would like to know.

    If anyone can answer my questions and also recomend some good literature related to gallium arsenide and optical temperature sensing i would be appreciated.
  2. jcsd
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