True Mobilities in Semi-Insulating O- and Cr-Doped GaAs

  • David Look


It is well known that an analysis of the magnetic field dependences of the resistivity ρ and Hall coefficient R, in nearly intrinsic material, will uniquely yield μ n, μ p, n, and p as long as single -carrier magnetic field dependences are not important. Unfortunately, recent data indicate that such effects are often important in semi-insulating GaAs and thus a new approach is necessary. We suggest an approach that requires only the usual, low field Hall effect and resistivity parameters, R0, and ρ0, but that also assumes knowledge of the intrinsic carrier concentration n¡, and the hole mobility μ p as a function of the electron mobility, i.e. μ p = f(μ n).We describe analyses which yield ni≏(2.6±0.5)×106 cm-3, and a tentative relationship for μ p namely, μ p -1 ≏ 9×10-4 + 13μ n -1 . Curves of μ n versus R0/ρ 0, with ρ 0 as a parameter, are calculated by using these relationships. For ρ 0 ≤4×106 Ω-cm, the only solutions are μ n ≈ R0/ρ 0 which means that simple Hall measurements will suffice for nearly all O-doped and undoped semi-insulating GaAs. For higher ρ 0, the solutions are double-valued, and means of selecting the proper solution are discussed. A simple compensation-distribution model is presented which yields the positions of the ‘O’ and Cr energy levels.


Hall Coefficient Magnetic Field Dependence Conductive Sample Mixed Conduction Intrinsic Carrier Concentration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    See, e.g., Putley, E.H. (1968). The Hall Effect and Semiconductor Physics, ch. 3. New York; DoverGoogle Scholar
  2. 2.
    Look, D.C. (1975). J. Phys. Chem. Solids, 36, 1311CrossRefGoogle Scholar
  3. 3.
    Look, D.C. (1977). J. Appl. Phys., 48, 5141CrossRefGoogle Scholar
  4. 4.
    Betko, J. and Merinsky, K. (1979). J. Appl. Phys., 50, 4212CrossRefGoogle Scholar
  5. 5.
    Willardson, R.K. and Duga, J.J. (1960). Proc. Phys. Soc. (London), 75, 280CrossRefGoogle Scholar
  6. 6.
    Cronin, G.R. and Haisty, R.W. (1964). J. Electrochem. Soc., 111, 874CrossRefGoogle Scholar

Copyright information

© David Look 1980

Authors and Affiliations

  • David Look
    • 1
  1. 1.Physics DepartmentUniversity of DaytonDaytonUSA

Personalised recommendations