Use of Langmuir Blodgett Thin Films for Rectification in Energy Harvesting Applications

Tunnel diodes have been found suitable for use in high frequency rectification for energy harvesting applications in a rectenna. For tunneling to take place in a metal insulator metal diode for rectification at THz frequencies, an ultrathin pinhole free insulating layer must be deposited between the metal layers for the diode to operate with small turn on voltages.

Langmuir Blodgett (LB) thin film deposition is a useful technique that allows the deposition of conformal, uniform monomolecular layers with a precise control of thickness. Organic compounds such as Vinyl Stearate, 10-12 Pentacosadiynoic Acid and Porphyrin were considered for deposition onto a Nickel film and were later topped with a small metal contact to complete the metal insulator metal diode assembly.

Several characterization techniques were used to check the quality of deposition of the thin insulator film and to analyze its material properties. UV spectroscopy, atomic force microscopy and infrared spectroscopy techniques were utilized for this purpose. An electrochemical study was performed with 10-12 Pentacosadiynoic acid deposited using the LB method on an Indium Tin Oxide coated glass substrate. Along with these characterization results, the current voltage characteristics of the diode behavior as well as its suitability for detection or energy harvesting will also be reported.