Most concepts for advanced photovoltaic devices rely on the transfer of charge between light absorbing semiconductors and conducting oxide films. Our incomplete understanding of the mechanisms that limit the efficiency of this charge transfer presents a challenge for research on photovoltaics. I will present results obtained via scanning probe spectroscopic studies (Kelvin force microscopy and scanning tunneling microscopy) of one widely-used transparent conducting oxide, ZnO:Al, that reveal the role of grain boundaries and oxygen defects in determining the efficiency of interfacial electron transport. Results obtained using planar Schottky barrier devices illustrate the promise and limitations of oxide electronics. Our results suggest a path forward for several new device concepts, including a hot electron solar cell based on resonant tunneling.
Coffee: 3:30 pm, 245 Compton