A validated predictive model of a-Si:H solar cell arrays was developed. The performance of a-Si:H solar cells was modeled by predicting the performance before degradation first, and then modifying it with terms that account for degradation and recovery effects. A unique approach for the determination of the fundamental rate controlling parameters for the degradation and recovery process was carried out by observing the variation of the short-circuit current. The experimental annealing of a-Si:H silicon samples showed that the percent recovery from the degraded state to the as-grown state by annealing was virtually independent of the initial state at the start of the annealing process. This allowed the recovery parameters to be determined independently of the prior degradation process. An extremely simple and fast running algorithm for the long-term performance was developed in terms of the incident solar radiation, the panel temperature, and the total radiation exposed. Also it was found that the entire process of the Staebler-Wronski effect could be adequately represented by a correlation in which the degradation and recovery processes are solely a function of the total radiation exposure of the panel at ambient conditions.

Silicon-germanium (SiGe) BiCMOS technology platforms have proven invaluable for implementing a wide variety of digital, RF, and mixed-signal applications in extreme environments such as space, where maintaining high levels of performance in the presence of low temperatures and background radiation is paramount. This work will focus on the investigation of the total-dose radiation tolerance of a third generation complementary SiGe:C BiCMOS technology platform. Tolerance will be quantified under proton and X-ray radiation sources for both the npn and pnp HBT, as well as for an operational amplifier built with these devices. Furthermore, a technique known as junction isolation radiation hardening will be proposed and tested with the goal of improving the SEE sensitivity of the npn in this platform by reducing the charge collected by the subcollector in the event of a direct ion strike. To the author's knowledge, this work presents the first design and measurement results for this form of RHBD.

This thesis evaluates the suitability of silicon-germanium technology for electronic systems intended for extreme environments, such as ambient temperatures outside of military specification (-55 degC to 125 degC) range and intense exposures to ionizing radiation. Silicon-germanium devices and circuits were characterized at cryogenic and high-temperatures (up to 300 degC) and exposed to ionizing radiation, providing empirical evidence that silicon-germanium is an excellent platform for terrestrial and space-based electronic applications.