Oxides for Rectenna Technology

Abstract

The quest to harvest untapped renewable infrared energy sources has led to significant research effort in design, fabrication and optimization of a self-biased rectenna that can operate without external bias voltage. At the heart of its design is the engineering of a high-frequency rectifier that can convert terahertz and infrared alternating current (AC) signals to usable direct current (DC). The Metal Insulator Metal (MIM) diode has been considered as one of the ideal candidates for the rectenna system. Its unparalleled ability to have a high response time is due to the fast, femtosecond tunneling process that governs current transport. This paper presents an overview of single, double and triple insulator MIM diodes that have been fabricated so far, in particular focusing on reviewing key figures of merit, such as zero-bias responsivity (β0), zero-bias dynamic resistance (R0) and asymmetry. The two major oxide contenders for MInM diodes have been NiO and Al2O3, in combination with HfO2, Ta2O5, Nb2O5, ZnO and TiO2. The latter oxide has also been used in combination with Co3O4 and TiOx. The most advanced rectennas based on MI2M diodes have shown that optimal (β0 and R0) can be achieved by carefully tailoring fabrication processes to control oxide stoichiometry and thicknesses to sub-nanometer accuracy.

Nanomaterials and Devices for Harvesting Ambient Electromagnetic Waves

“…This is one of many examples of rectennas using MIM diodes, with a recent review available in [ 8 ]. We note that rectennas integrated with MIM diodes can also work at 1–3 THz and at 28 THz.…”

“…MIM diodes have been used for many years mainly for THz and infrared detection, e.g., using a 1 nm thick NiO layer as insulator [ 58 ]. Many other thin oxides with a thickness in the range 1–3 nm have also been used over the years with satisfactory results [ 8 ]. Beyond these results, there are several new solutions based on advanced knowledge of nanomaterials.…”

“…Depending on the requested DC power, these rectennas can be arranged in arrays with various configurations involving one or more diodes. Many new materials are involved in the gathering of this ambient EM energy, such as two-dimensional (2D) materials (e.g., graphene and MoS 2 ) [ 6 , 7 ], oxides [ 8 ], and nanoscale ferroelectrics (e.g., HfO 2 -based ferroelectrics) [ 9 ].…”

Parallel metal–insulator–metal diode with an ultrathin spin-coated hydrogen silsesquioxane insulating layer

“…[18][19][20][21] The tunneling phenomenon of electrons in MIM diodes, that is, passing through an extremely thin insulator from one to another metal electrode, takes place in the order of fs, enabling the diodes to operate at ultrahigh frequencies. 22) The thin insulator in MIM, usually in the range of 1 ∼ 5 nm, has a great effect on the figures of merit of MIM diodes. [22][23][24] Poor-quality insulators may cause serious problems such as the direct connection of electrodes if there exist some pinholes in the insulating layer.…”

“…22) The thin insulator in MIM, usually in the range of 1 ∼ 5 nm, has a great effect on the figures of merit of MIM diodes. [22][23][24] Poor-quality insulators may cause serious problems such as the direct connection of electrodes if there exist some pinholes in the insulating layer. Thick insulators often exponentially reduce the possibility of tunneling and significantly increase the resistance of a MIM diode.…”