SILICON QUANTUM DOTS: APPLICATION FOR ENERGY SELECTIVE CONTACTS TO HOT CARRIERSOLAR CELLS

摘要

Energy selective contacts using the resonant tunneling mechanism for carrier extraction have been proposed for hot carrier solar cells. Size controlled silicon quantum dots, providing three-dimensional energy confinement, embedded in the centre of an oxide layer may be applied for this resonant tunneling extraction purpose. Structures with such arrangement were fabricated by high temperature annealing of the RF sputtered SiO2/siliconrich-oxide (SRO) /SiO2 layers. This method has the advantage of producing a single layer of size-controlled selforganizedSi quantum dots by controlling the thickness of the SRO film. Metal-Oxide-Semiconductor (MOS) type devices with Si dots around 4 nm in diameter in the centre of the oxide layer were made on an n-type degenerate substrate for electrical characterization. DC I-V curves with negative differential resistance type characteristics have been measured. This reveals an increase in carrier transmission that may possibly be due to resonant tunneling over a small energy range.