Electrical measurements of the equilibrium np product (n2ie) in heavily doped n‐ and p‐GaAs were performed. The n2ieDproduct (where D is the diffusivity) was measured by fitting the collector current‐voltage characteristic of a homojunction bipolar transistor to an ideal diode equation modified to account for transport in thin base transistors.The n2ie product was then extracted from n2ieD by utilizing diffusivity results obtained with the zero‐field time‐of‐flight technique. Our results show significant effective band‐gap shrinkage in heavily doped p‐GaAs, and very little effective band‐gap shrinkage in heavily doped n‐GaAs. At extremely heavy dopings, an effective band‐gap widening is observed for both n‐ and p‐GaAs and is attributed to the effects of degeneracy.


Copyright (1993) 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. 64 (4), 24 January 1994 and may be found at http://dx.doi.org/10.1063/1.111110. The following article has been submitted to/accepted by Applied Physics Letters. Copyright (1994) E. S. Harmon, M. R. Melloch, and M. S. Lundstrom. This article is distributed under a Creative Commons Attribution 3.0 Unported License.

Date of this Version


Published in:

Applied Physics Letters



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.