Paper TF+AS+NS+SE-WeA3
GLAD-ALD Core-Shell Nanorod Arrays for Solar Cell Applications

Wednesday, October 30, 2013, 2:40 pm, Room 102 C

In a nanostructured photovoltaic cell, one should take into consideration the competing effects of enhanced light absorption and shorter carrier collection lengths that both lead to improved photo-conversion efficiencies, and negative effects due to the larger amounts of surface recombination events. However, a key limitation to systematically investigating this in detail originates from the disordered random network nature and the wide particle size distribution of nanostructured geometries studied in the past. In addition, most of the nanofabrication methods that can produce uniform nanostructure geometries are limited to certain material systems. Therefore, it is essential to develop innovative low-cost solar cell fabrication approaches that can provide semiconductor nanostructures of a variety of materials with uniform and optimized geometries for improving cell efficiencies. In this work, we demonstrate a novel nanostructured solar cell fabrication method using core-shell radial junction nanorod arrays, which can potentially offer superior conversion efficiencies compared to conventional planar designs. Nanorod arrays of metallic/semiconductor materials (core) were produced by utilizing glancing angle deposition (GLAD) technique. GLAD metallic nanorods were made of molybdenum (Mo) and semiconducting ones were indium sulfide (In₂S₃). For the fabrication of proof-of-concept nanostructured photovoltaic cells, we conformally coated GLAD nanorods with semiconducting metal-oxide layers (shell) of zinc oxide (ZnO) and titanium dioxide (TiO₂) using atomic layer deposition (ALD) method. Our preliminary structural, optical, electrical, and solar cell characterization results are presented.