The capacitor, which features embedded metal nanoparticles, is said to be similar to a metal-insulator-metal (MIM) diode and to have the potential to enhance wireless capability for information processing, sensing and telecommunications.
“We have developed a capacitor with the ability to tune the capacitance by large amounts using light, said Professor Gadi Eisenstein, pictured. “Such changes are not possible in any other device. The observed photo sensitivity of this MIS diode structure expands its potential in optoelectronic circuits that can be used as a light-sensitive variable capacitor in remote sensing circuits.”
The researchers created three MIS structures, fabricated on a bulk silicon substrate, based on a multilayer dielectric stack, which consisted of a thin thermal silicon dioxide film and a hafnium oxide layer. The two layers were separated by strontium fluoride (SrF2) sublayers in which iron or cobalt nanoparticles were embedded.
Comparison of additional test structures concluded that only devices consisting of the combination of Fe and SrF2 turn the MIS structure into a photo-sensitive MIM-like structure.