TY - JOUR
T1 - Controlling the work function of ZnO and the energy-level alignment at the interface to organic semiconductors with a molecular electron acceptor
AU - Schlesinger, Raphael
AU - Xu, Yong
AU - Hofmann, Oliver T.
AU - Winkler, Stefanie
AU - Frisch, Johannes
AU - Niederhausen, Jens
AU - Vollmer, Antje
AU - Blumstengel, Sylke
AU - Henneberger, Fritz
AU - Rinke, Patrick
AU - Scheffler, Matthias
AU - Koch, Norbert
PY - 2013/4/22
Y1 - 2013/4/22
N2 - We show that the work function (Φ) of ZnO can be increased by up to 2.8 eV by depositing the molecular electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). On metals, already much smaller Φ increases involve significant charge transfer to F4TCNQ. No indication of negatively charged F4TCNQ on ZnO is found by photoemission spectroscopy. This fundamental difference is explained by a simple electrostatic model that identifies the bulk doping and band bending in ZnO as key parameters. Varying Φ of the inorganic semiconductor enables tuning the energy-level alignment at ZnO/organic semiconductor interfaces.
AB - We show that the work function (Φ) of ZnO can be increased by up to 2.8 eV by depositing the molecular electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). On metals, already much smaller Φ increases involve significant charge transfer to F4TCNQ. No indication of negatively charged F4TCNQ on ZnO is found by photoemission spectroscopy. This fundamental difference is explained by a simple electrostatic model that identifies the bulk doping and band bending in ZnO as key parameters. Varying Φ of the inorganic semiconductor enables tuning the energy-level alignment at ZnO/organic semiconductor interfaces.
UR - http://www.scopus.com/inward/record.url?scp=84877045025&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.87.155311
DO - 10.1103/PhysRevB.87.155311
M3 - Article
AN - SCOPUS:84877045025
SN - 1098-0121
VL - 87
JO - Physical Review B
JF - Physical Review B
IS - 15
M1 - 155311
ER -