We have studied the capacitance-voltage (C- V) characteristics of Schottky barriers on inverted nGaAs/ N-AIGaAs and normal N-AIGaAs/n-GaAs heterojunctions. Impurities introduced during film growth produced a negative sheet charge of 6.0 X 10 II cm -2 at the interface of the inverted n-GaAs/N-AIGaAs heterojunction. The effectiveness of GaAs quantum wells in trapping these impurities was investigated. GaAs quantum wells 20 A wide were placed in intervals of 2500 A for the first 0.75 pm of the AIGaAs layer; in the last 0.25 pm, the periodicity of the quantum wells was progressively decreased by half with the last quantum well placed at about 160 A from the GaAs/ AIGaAs interface. The resulting measured interface charge concentration of 4.4 X 1010 cm -2 is more than a magnitude lower than measured before the use of the quantum wells and is essentially at the limit of the accuracy of the C-V technique for this structure.


Copyright (1986) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Appl. Phys, Lett. 48 (6), 10 February 1986 and may be found at http://dx.doi.org/10.1063/1.96520. The following article has been submitted to/accepted by Applied Physics Letters. Copyright (1986) K. L. Tan, M. S. Lundstrom, and M. R. Melloch. This article is distributed under a Creative Commons Attribution 3.0 Unported License.

Date of this Version




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Appl. Phys. Lett. 48, 428 (1986)



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