Campbell, Joe2011-07-112017-05-112011-07-112017-05-112003-08http://hdl.handle.net/2152/12230A Monte Carlo simulation model is developed. The low-noise behavior of AlGaAs/GaAs avalanche photodiodes (APDs) is successfully simulated and is explained as spatial localization of impact ionization events. The noise is sensitive to initial carrier energy and we point out that energetic and hot electrons should be distinguished. This model also successfully explains the measured exponential gain curve and “noiseless” behavior of HgCdTe APDs. I demonstrate that this model can aid the design of high-speed InGaAs/InAlAs APDs. Model parameters are constrained with low-temperature measurements of APD gain and noise in this work. I have also suggested a new shot noise suppression mechanism associated with multiplication gain.electronicengCopyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.Avalanche photodiodesMonte Carlo methodThesisRestricted