Document Type


Publication Date



The room‐temperature spectral detectivity of Cr‐doped GaAs has been examined in the impurity excitation region out to 1.7 μ, a range which includes the wavelengths of several important lasers as well as low‐loss optical fibers. The results include values of D∗ greater than 1011 cm Hz1/2/W in the photoconductive mode, and 1010 cm Hz1/2/W in the photomagnetoelectric mode. Small carrier lifetimes, ∼10−8 sec, offer the potential of high‐speed operation; however, the measured response times are much larger, ∼10−3–10−2 sec, because of very high input impedances. Formulas are presented to show the variation of D∗ with relevant parameters, and means of improving the performance are discussed.


Copyright © 1978, 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 the Journal of Applied Physics 49.6, and may be found at



Included in

Physics Commons