Study of Metal-Insulator-Metal Diodes for Photodetection

by Li Li

Institution: University of Dayton
Department: Electro-Optics
Degree: MS(M.S.)
Year: 2013
Keywords: Electrical Engineering; Photodetector; Quantum tunneling effect; Metal-insulator-metal structure; responsivity; quantum confinement; dark current.
Record ID: 2001099
Full text PDF: http://rave.ohiolink.edu/etdc/view?acc_num=dayton1367319217


We study the optical responsivity of metal-insulator-metal (MIM) devices using different metals, but at least one metal with displaying plasmonic resonance characteristics. We apply quantum mechanical tunneling and equilibrium electron statistics to calculate the current density for the MIM structure with forward and backward bias voltages. We also examine the tunneling properties for nanoslabs and nanorods which alter the electron density of states by laterally confining the electrons and lead to a change of the tunneling current.To calculate the quantum tunneling current we use two methods for solving Schrodinger’s equation: Transfer Matrix Method (TMM) and Shooting method to simulate tunneling probability current through the insulating gap. Both methods are in excellent agreement. The tunneling current performance of MIM nanostructure is determined by the size and shape of insulator gap. Using the quantum results we calculate the DC and AC current of MIM nanostructures when an electromagnetic field is applied. The electrons tunnel through the insulating gap driven by an electromagnetic field using a photon assisted tunneling expression. Finally, the results for the DC and AC current are evaluated to determine the MIM responsivity from the long wavelength infrared (IR) regime to the near IR regime.