Silicon nanocrystals in an oxide matrix for thin film solar cells with 492 mV open circuit voltage

We have fabricated solar cells with layers of co-sputtered silicon and silicon dioxide. The diode structures were fabricated by sputtering alternating layers of SiO2 and silicon rich oxide onto quartz substrates with in-situ boron, for p-type, and phosphorus, for n-type, doping. After crystallization at 1100 °C, isolated Si-nanocrystals are formed. The thin film layers containing these crystals act as n-type or p-type semiconductors as determined from CV measurements on MOS structures. The dark and illuminated I–Vs of the fabricated diodes show a rectifying behavior with an open circuit voltage of 492 mV under a simulated 1.5AMD illumination. A circuit model is proposed to explain the observed I–V characteristics.