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Origin of Voltage‐Dependent High Ideality Factors in Graphene–Silicon Diodes
Author(s) -
Park HongKi,
Choi Jaewu
Publication year - 2018
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201700317
Subject(s) - graphene , materials science , optoelectronics , raman spectroscopy , heterojunction , silicon , diode , capacitance , voltage , dielectric spectroscopy , nanotechnology , electrical engineering , electrode , chemistry , optics , physics , engineering , electrochemistry
Undoubtedly graphene–silicon (GS) heterostructure devices will play significant roles as future rectifiers, potential barrier modulators, photodetectors, photovoltaic devices, biochemical sensors, and so on. However, typical GS devices suffer from unusually wide‐range voltage‐dependent high ideality factors (η = 1.1–33.5). To overcome this hurdle, the origin of this wide‐range voltage‐dependent ideality factor should first be identified but this has not yet been fully studied. This study focuses on identifying the origin using impedance spectroscopy in conjunction with current–voltage, Raman, and X‐ray photoemission spectroscopy. The impedance spectra are analyzed with an equivalent distributed circuit model that accounts for the voltage‐dependent resistance and capacitance of graphene, the graphene–metal contact, the silicon interface states, and the nonequilibrium behavior in GS junction. This study clearly shows that the voltage‐dependent resistance and capacitance of interface states, graphene, and graphene–metal contact are responsible for the wide‐range voltage‐dependent high ideality factors. This study provides a potential method to overcome the drawbacks of GS devices.