Si SiO2 quantum well and quantum dot structures atomic scale preparation and characterization with respect to photovoltaic application

Abstract

Si SiO2 single quantum wells and quantum dot layers were prepared under ultrahigh vacuum conditions in order to study their structural, chemical and photo electrical properties with respect to a possible application in photovoltaic devices. Particular focus is put on the realization of well defined and abrupt interfaces with low densities of interface gap states. The detection of a photocurrent in these quantum structures is demonstrated. Its spectral dependence correlates with the respective structural properties. Internal quantum efficiencies of photoconductivity and, thus, carrier mobility lifetime products are strongly affected by Si SiO2 interface states and were significantly enhanced upon hydrogen treatment due to passivation of interface gap state