skip to main content

Title: Investigation of significantly high barrier height in Cu/GaN Schottky diode

Current-voltage (I-V) measurements combined with analytical calculations have been used to explain mechanisms for forward-bias current flow in Copper (Cu) Schottky diodes fabricated on Gallium Nitride (GaN) epitaxial films. An ideality factor of 1.7 was found at room temperature (RT), which indicated deviation from thermionic emission (TE) mechanism for current flow in the Schottky diode. Instead the current transport was better explained using the thermionic field-emission (TFE) mechanism. A high barrier height of 1.19 eV was obtained at room temperature. X-ray photoelectron spectroscopy (XPS) was used to investigate the plausible reason for observing Schottky barrier height (SBH) that is significantly higher than as predicted by the Schottky-Mott model for Cu/GaN diodes. XPS measurements revealed the presence of an ultrathin cuprous oxide (Cu{sub 2}O) layer at the interface between Cu and GaN. With Cu{sub 2}O acting as a degenerate p-type semiconductor with high work function of 5.36 eV, a high barrier height of 1.19 eV is obtained for the Cu/Cu{sub 2}O/GaN Schottky diode. Moreover, the ideality factor and barrier height were found to be temperature dependent, implying spatial inhomogeneity of barrier height at the metal semiconductor interface.
Authors:
; ;  [1] ; ;  [2]
  1. Department of Physics, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi-110016 (India)
  2. Department of Micro and Nanosciences, Aalto University, P.O. Box 13500, FI-00076, Aalto (Finland)
Publication Date:
OSTI Identifier:
22492405
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 1; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COPPER; COPPER OXIDES; ELECTRIC POTENTIAL; EPITAXY; EV RANGE; FIELD EMISSION; FILMS; GALLIUM NITRIDES; INTERFACES; LAYERS; SCHOTTKY BARRIER DIODES; SEMICONDUCTOR MATERIALS; TEMPERATURE DEPENDENCE; THERMIONIC EMISSION; WORK FUNCTIONS; X-RAY PHOTOELECTRON SPECTROSCOPY