APPLICATIONS OF TECHNOLOGY:
Junctionless devices used for
- Solar cells
- Light Emitting Diodes
Using an ultrathin (~15 nm in thickness) molybdenum oxide (MoOx , x<3) layer as a transparent hole selective contact to n-type silicon, researchers at Berkeley Lab demonstrated a room-temperature processed oxide / silicon solar cell with a power conversion efficiency of 14.3%. While MoOx is commonly considered to be a semiconductor with a band gap of 3.3 eV, from X-ray photoelectron spectroscopy, the researchers showed that MoOx may be considered to behave as a high workfunction metal with a low density of states at the Fermi level originating from the tail of an oxygen vacancy-derived defect band located inside the band gap.
Specifically, in the absence of carbon contamination, they measured a work function potential of ~6.6 eV, which is significantly higher than that of all elemental metals. Their results on the archetypical semiconductor silicon demonstrate the use of nm-thick transition metal oxides as a simple and versatile pathway for dopant-free contacts to inorganic semiconductors. This work has important implications toward enabling a novel class of junctionless devices with applications for solar cells, light emitting diodes, photodetectors and transitors.
For more details, see the researchers' publication in NanoLetters, linked below.
FOR MORE INFORMATION:
Battaglia, C., Yin, X., Zheng, M., Sharp, I.D., Chen, T., McDonnell, S., Azcatl, A., Carraro, C., Ma, B., Maboudian, R., Wallace, R. M., Javey, A. “Hole Selective MoOx Contact for Silicon Solar Cells,” NanoLetters, 2014, 14, 967-971.
STATUS: Patent pending. Available for licensing or collaborative research.
REFERENCE NUMBER: 2014-010