Advancements in spacecraft solar array technologies require radiation hard, high temperature discrete diodes for cell bypass protection and string blocking diodes. These diodes are constantly exposed to various types of high energy radiation including energetic electrons and protons. These radiations produce detrimental effects in the electronics ranging from temporary device characteristics to catastrophic failure. In this SBIR Phase II project, we propose heterojunction diode technology that is capable of operating at low voltages and extreme condition conditions (intense UV radiation, electrons and proton exposures, and extreme temperatures in space environment). Our prototypes indicate that heterojunction diodes are tunable for low voltage operation and low degradation in extreme conditions of temperatures and electron beam irradiation. High temperature, high voltage, and radiation hard diodes can handle larger solar cells (>30cm2) and flex blankets where bypass diodes may experience temperatures beyond which silicon based or conventional diode technology is not suitable. Thus, the future for new integrated devices for space and high-voltage and high-power electronics is promising for DODÂ’s Programs. This research can provide DOD and consumer electronics low cost and enabling technology in advancing protection of space power solar cell panels with anticipation in transition to Phase III.