Hybrid systems consisting of organic molecules at inorganic semiconductor surfaces are gaining increasing importance as thin film devices for optoelectronics. The efficiency of such devices strongly depends on the collective behavior of the adsorbed molecules. In the present paper, we propose a novel, coarse-grained model addressing the condensed phases of a representative hybrid system, that is, para-sexiphenyl (6P) at zinc-oxide (ZnO). Within our model, intermolecular interactions are represented via a Gay-Berne potential (describing steric and van-der-Waals interactions) combined with the electrostatic potential between two linear quadrupoles. Similarly, the molecule-substrate interactions include a coupling between a linear molecular quadrupole to the electric field generated by the line charges characterizing ZnO(10-10). To validate our approach, we perform equilibrium Monte Carlo simulations, where the lateral positions are fixed to a 2D lattice, while the rotational degrees of freedom are continuous. We use these simulations to investigate orientational ordering in the condensed state. We reproduce various experimentally observed features such as the alignment of individual molecules with the line charges on the surface, the formation of a standing uniaxial phase with a herringbone structure, as well as the formation of a lying nematic phase.

1.
R.
Koch
,
J. J.
Finnerty
, and
T.
Bruhn
,
J. Phys. Org. Chem.
21
,
954
(
2008
).
2.
J.
Roales
,
J. M.
Pedrosa
,
P.
Castillero
,
M.
Cano
,
T. H.
Richardson
,
Á.
Barranco
, and
A. R.
González-Elipe
,
ACS Appl. Mater. Interfaces
4
,
5147
(
2012
).
3.
H.
Li
,
R.
Zheng
, and
Q.
Shi
,
J. Phys. Chem. C
116
,
11886
(
2012
).
4.
G.
Hlawacek
and
C.
Teichert
,
J. Phys.: Condens. Matter
25
,
143202
(
2013
).
5.
E.
Zojer
,
N.
Koch
,
P.
Puschnig
,
F.
Meghdadi
,
A.
Niko
,
R.
Resel
,
C.
Ambrosch-Draxl
,
M.
Knupfer
,
J.
Fink
,
J. L.
Brédas
, and
G.
Leising
,
Phys. Rev. B
61
,
16538
(
2000
).
6.
C.
Simbrunner
,
Semicond. Sci. Technol.
28
,
053001
(
2013
).
7.
C.
Simbrunner
,
D.
Nabok
,
G.
Hernandez-Sosa
,
M.
Oehzelt
,
T.
Djuric
,
R.
Resel
,
L.
Romaner
,
P.
Puschnig
,
C.
Ambrosch-Draxl
,
I.
Salzmann
,
G.
Schwabegger
,
I.
Watzinger
, and
H.
Sitter
,
J. Am. Chem. Soc.
133
,
3056
(
2011
).
8.
D. D.
Vvedensky
, in
Low-Dimensional Semiconductor Structures: Fundamentals and Device Applications
, edited by
K.
Barnham
(
Cambridge University Press
,
Cambridge
,
2009
).
9.
U. W.
Pohl
,
Epitaxy of Semiconductors
(
Springer Verlag
,
Berlin
,
2013
).
10.
P.
Clancy
,
Chem. Mater.
23
,
522
(
2011
).
11.
R.
Resel
,
J. Phys.: Condens. Matter
20
,
184009
(
2008
).
12.
S.
Blumstengel
,
S.
Sadofev
, and
F.
Henneberger
,
New J. Phys.
10
,
065010
(
2008
).
13.
A. S.
Komolov
,
P. J.
Møller
,
J.
Mortensen
,
S. A.
Komolov
, and
E. F.
Lazneva
,
Surf. Sci.
586
,
129
(
2005
).
14.
S.
Blumstengel
,
H.
Glowatzki
,
S.
Sadofev
,
N.
Koch
,
S.
Kowarik
,
J. P.
Rabe
, and
F.
Henneberger
,
Phys. Chem. Chem. Phys.
12
,
11642
(
2010
).
15.
C.-Y.
Huang
,
C.-C.
Yang
,
H.-C.
Yu
, and
Y.-C.
Chen
,
J. Appl. Phys.
115
,
083109
(
2014
).
16.
F.
Tong
,
K.
Kim
,
D.
Martinez
,
R.
Thapa
,
A.
Ahyi
,
J.
Williams
,
D.-J.
Kim
,
S.
Lee
,
E.
Lim
,
K. K.
Lee
, and
M.
Park
,
Semicond. Sci. Technol.
27
,
105005
(
2012
).
17.
S.
Berkebile
,
P.
Puschnig
,
G.
Koller
,
M.
Oehzelt
,
F. P.
Netzer
,
C.
Ambrosch-Draxl
, and
M. G.
Ramsey
,
Phys. Rev. B
77
,
115312
(
2008
).
18.
S.
Berkebile
,
T.
Ules
,
P.
Puschnig
,
L.
Romaner
,
G.
Koller
,
A. J.
Fleming
,
K.
Emtsev
,
T.
Seyller
,
C.
Ambrosch-Draxl
,
F. P.
Netzer
, and
M. G.
Ramsey
,
Phys. Chem. Chem. Phys.
13
,
3604
(
2011
).
19.
K.-F.
Braun
and
S.-W.
Hla
,
Nano Lett.
5
,
73
(
2005
).
20.
F.
Della Sala
,
S.
Blumstengel
, and
F.
Henneberger
,
Phys. Rev. Lett.
107
,
146401
(
2011
).
21.
J. E.
Goose
,
E. L.
First
, and
P.
Clancy
,
Phys. Rev. B.
81
,
205310
(
2010
).
22.
G.
Hlawacek
,
P.
Puschnig
,
P.
Frank
,
A.
Winkler
,
C.
Ambrosch-Draxl
, and
C.
Teichert
,
Science
321
,
108
(
2008
).
23.
T.
Potocar
,
S.
Lorbek
,
D.
Nabok
,
Q.
Shen
,
L.
Tumbek
,
G.
Hlawacek
,
P.
Puschnig
,
C.
Ambrosch-Draxl
,
C.
Teichert
, and
A.
Winkler
,
Phys. Rev. B
83
,
075423
(
2011
).
24.
E. P.
Socci
,
B. L.
Farmer
, and
W. W.
Adams
,
J. Polym. Sci., Part B: Polym. Phys.
31
,
1975
(
1993
).
25.
G.
Koller
,
S.
Berkebile
,
J. R.
Krenn
,
F. P.
Netzer
,
M.
Oehzelt
,
T.
Haber
,
R.
Resel
, and
M. G.
Ramsey
,
Nano Lett.
6
,
1207
(
2006
).
26.
L.
Tumbek
,
C.
Gleichweit
,
K.
Zojer
, and
A.
Winkler
,
Phys. Rev. B
86
,
085402
(
2012
).
27.
J. S.
Raut
and
K. A.
Fichthorn
,
J. Chem. Phys.
108
,
1626
(
1998
).
28.
J. S.
Raut
and
K. A.
Fichthorn
,
J. Chem. Phys.
110
,
587
(
1999
).
29.
R.
Ruiz
,
D.
Choudhary
,
B.
Nickel
,
T.
Toccoli
,
K.-C.
Chang
,
A. C.
Mayer
,
P.
Clancy
,
J. M.
Blakely
,
R. L.
Headrick
,
S.
Iannotta
, and
G. G.
Malliaras
,
Chem. Mater.
16
,
4497
(
2004
).
30.
D.
Choudhary
,
P.
Clancy
,
R.
Shetty
, and
F.
Escobedo
,
Adv. Funct. Mater.
16
,
1768
(
2006
).
31.
P. K.
Jana
and
A.
Heuer
,
J. Chem. Phys.
138
,
124708
(
2013
).
32.
S. F.
Hopp
and
A.
Heuer
,
J. Chem. Phys.
136
,
154106
(
2012
).
33.
J.
Kundu
and
R.
Rajesh
,
Phys. Rev. E.
89
,
052124
(
2014
).
34.
T.
Fischer
and
R. L. C.
Vink
,
Europhys. Lett.
85
,
56003
(
2009
).
35.
R.
Dickman
,
J. Chem. Phys.
136
,
174105
(
2012
).
36.
X.
Feng
,
H. W. J.
Blte
, and
B.
Nienhuis
,
Phys. Rev. E
83
,
061153
(
2011
).
37.
R.
Shekhar
,
J. K.
Whitmer
,
R.
Malshe
,
J. A.
Moreno-Razo
,
T. F.
Roberts
, and
J. J.
de Pablo
,
J. Chem. Phys.
136
,
234503
(
2012
).
38.
A. M.
Luo
,
S.
Wenk
, and
P.
Ilg
,
Phys. Rev. E
90
,
022502
(
2014
).
39.
N.
Ghoshal
,
K.
Mukhopadhyay
, and
S. K.
Roy
,
Phys. Rev. E
89
,
042505
(
2012
).
40.
K. Palczynski and J. Dzubiella, private communication 2014.
41.
J. G.
Gay
and
B. J.
Berne
,
J. Chem. Phys.
74
,
3316
(
1981
).
42.
D. J.
Cleaver
,
C. M.
Care
,
M. P.
Allen
, and
M. P.
Neal
,
Phys. Rev. E
54
,
559
(
1996
).
43.
P.
Golubkov
and
P.
Ren
,
J. Chem. Phys.
125
,
064103
(
2006
).
44.

Note that the Gay-Berne potential43 displays an artifact for strongly anisotropic molecules, which attract each other under conditions of high overlap. In order to circumvent this artifact we assign to configurations with rij0.9σ(ui,uj,rˆij) a large energy “penalty.”

45.
J.
Stelzer
,
P.
Galatola
,
G.
Barbero
, and
L.
Longa
,
Phys. Rev. E
55
,
477
(
1997
).
46.
H.
Steuer
,
S.
Hess
, and
M.
Schoen
,
Phys. Rev. E
69
,
031708
(
2004
).
47.
D.
Micheletti
,
L.
Muccioli
,
R.
Berardi
,
M.
Ricci
, and
C.
Zannoni
,
J. Chem. Phys.
123
,
4224705
(
2005
).
48.
F.
Barmes
and
D. J.
Cleaver
,
Phys. Rev. E
71
,
021705
(
2005
).
49.
T.
Gruhn
and
M.
Schoen
,
J. Chem. Phys.
108
,
9124
(
1998
).
50.
J.-P.
Hansen
and
I.
McDonald
,
Theory of Simple Liquids
, 3rd ed. (
Elsevier Academic Press
,
London
,
2006
).
51.
MarvinSketch by ChemAxon, version 6.0, used via www.reaxys.com, 5 February 2014.
52.
K.
Palczynski
,
G.
Heimel
,
J.
Heyda
, and
J.
Dzubiella
,
Cryst. Growth Des.
14
,
3791
(
2014
).
53.
C.
Gray
and
K.
Gubbins
,
Theory of Molecular Fluids. Volume 1: Fundamentals
(
The Clarendon Press, Oxford University Press
,
New York
,
1984
).
54.
T. M.
Parker
,
N. G.
Condon
,
R.
Lindsay
,
F. M.
Leibsle
, and
G.
Thornton
,
Surf. Sci.
415
,
1046
(
1998
).
55.
M. P.
Allen
and
D. J.
Tildesley
,
Computer Simulation of Liquids
(
The Clarendon Press, Oxford University Press
,
New York
,
1987
).
56.
D. A.
Strehober
,
H.
Engel
, and
S. H. L.
Klapp
,
Phys. Rev. E
88
,
012505
(
2013
).
57.
D.
Andrienko
,
M. P.
Allen
,
G.
Skacej
, and
S.
Zumer
,
Phys. Rev. E
65
,
041702
(
2002
).
58.
D.
Andrienko
,
M.
Tasinkevych
,
P.
Patricio
, and
M. M.
Telo da Gama
,
Phys. Rev. E
69
,
021706
(
2004
).
59.
P.
Bolhuis
and
D. J.
Frenkel
,
J. Chem. Phys.
106
,
666
(
1997
).
60.
K.
Al-Shamery
,
H. G.
Rubahn
, and
H.
Sitter
,
Organic Nanostructures for Next Generation Devices
(
Springer Verlag
,
Berlin
,
2009
).
61.
Y.
Garmshausen
,
J.
Schwarz
,
J.
Hildebrandt
,
B.
Kobin
,
M.
Pätzel
, and
S.
Hecht
,
Org. Lett.
16
,
2838
(
2014
).
62.
I.
Salzmann
,
S.
Duhm
,
G.
Heimel
,
M.
Oehzelt
,
R.
Kniprath
,
R. L.
Johnson
,
J. P.
Rabe
, and
N.
Koch
,
J. Am. Chem. Soc.
39
,
12870
(
2008
).
63.
S. Blumstengel, private communication 2014.
You do not currently have access to this content.