High Efficiency InGaN Solar Cells

This Phase I SBIR program will demonstrate the feasibility of fabricating high efficiency solar cells based on InGaN photovoltaic devices using MBE for material parameter optimization and MOCVD for manufacturability. Recent results demonstrating that InN has a much narrower bandgap than previously believed open the door to fabrication of photovoltaic devices responsive from the near infrared through UV ranges. Thus, unprecedented efficiencies should be possible. Currently, Structured Materials Industries (SMI) and Cornell University are conducting a Phase I STTR in InGaN solar cell development. In this program we have identified that crucial developments in InN and In-rich InGaN are the key to realizing the potential of InGaN full spectrum solar cells. Specifically, (1) the achievement of thick (>2 m), adherent InN layers; (2) p-type doping in InN; and (3) understanding and control of surface carriers. In this program we propose to focus on and solve these important material issues. In Phase I, together with Dr. William Schaff of Cornell University, a pioneer in InN and InGaN technology, SMI will deposit InN and In-rich InGaN films and evaluate deposition and post-processing parameters enabling these material goals. Fabrication and demonstration of prototype devices and process scale-up will take place in Phase II.