This proposal on "Electronic Transport in Amorphous Silicon Multilayers," between Dr. Hellmut Fritzsche of the University of Chicago and Professor CHEN Kunji of Nanjing University, is jointly sponsored by NSF and the State Educational Commission (SEDC) of China. The investigators point out that with amorphous semiconductors, it is possible to make ultrathin multilayers (superlattices) cheaper and out of many more materials than it is with crystalline semiconductors (microchips), as well as to extend the device possibilities to large sized applications inappropriate for small, fragile crystals. These amorphous semiconductors, consisting of hundreds of ultra thin layers of hydrogenated amorphous silicon and other materials, each layer either a few atomic layers thick to hundreds of atoms thick, possess several useful new transport properties which cannot be obtained in unlayered semiconductors, namely metastable conductance states which are produced by a short light pulse or by a high bias voltage. The quasi two dimensional nature of these multilayers allows new material properties to be designed. The investigators will explore the relation of these metastable and bistable conductance processes with the structure, defect concentration, and the hydrogen content of the multilayers.
