Atomic Layer Deposition of Al2O3 on WSe2 Functionalized by Titanyl Phthalocyanine.
To deposit an ultrathin dielectric onto WSe2, monolayer titanyl phthalocyanine (TiOPc) is deposited by molecular beam epitaxy as a seed layer for atomic layer deposition (ALD) of Al2O3 on WSe2. TiOPc molecules are arranged in a flat monolayer with 4-fold symmetry as measured by scanning tunneling microscopy. ALD pulses of trimethyl aluminum and H2O nucleate on the TiOPc, resulting in a uniform deposition of Al2O3, as confirmed by atomic force microscopy and cross-sectional transmission electron microscopy. The field-effect transistors (FETs) formed using this process have a leakage current of 0.046 pA/μm(2) at 1 V gate bias with 3.0 nm equivalent oxide thickness, which is a lower leakage current than prior reports. The n-branch of the FET yielded a subthreshold swing of 80 mV/decade.
Jun Hong
JH
Park
Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States.
Sara
S
Fathipour
Iljo
I
Kwak
Kasra
K
Sardashti
Christopher F
CF
Ahles
Steven F
SF
Wolf
Mary
M
Edmonds
Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States.
Suresh
S
Vishwanath
Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States.
Huili Grace
HG
Xing
Department of Chemical and Petroleum Engineering, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States.
Susan K
SK
Fullerton-Shirey
Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States.
Alan
A
Seabaugh
Andrew C
AC
Kummel
ALD; Al2O3; TiOPc; WSe2; device