Nonstoichiometric Nanolayered Ni/nio/al2o3/crau Metal− Insulator−metal Infrared Rectenna

Résumé: Metal−insulator−metal (MIM) diodes with a high cutoff frequency are needed for efficient infrared rectification in optical rectenna systems. Such diodes require low resistance, low capacitance, and high nonlinearity, which are hard to achieve simultaneously. Al2O3, with its low dielectric constant of 0.8 at a wavelength of 10.6 μm, offers low capacitance at the price of large diode resistance due to the high barrier it forms with metals. We demonstrate a low-resistance (<2 kΩ) double-insulator Ni/NiO/ Al2O3/CrAu diode with a small area of 0.025 μm2 . We engineered a subnanometer-thick and nonstoichiometric Al2O3, which forms a smaller barrier with the adjacent metal than that for stoichiometric Al2O3, resulting in a lower resistance. To verify the expected enhancement in efficiency due to lower resistance and capacitance, we compare the diodes’ performance at optical frequencies to what has been published to date. NiO/Al2O3 double-insulator− metal−insulator−metal (MI2M) rectennas demonstrate improved total conversion efficiencies and detectivities beyond the best achieved previously for a structure that does not take advantage of resonant tunneling

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