TY - JOUR

T1 - Electronic properties of a zinc oxide surface modified by ultra-thin layers of conjugated organic molecules

AU - Komolov, AS

AU - Moller, PJ

AU - Mortensen, J

AU - Komolov, SA

AU - Lazneva, EF

PY - 2005/7/20

Y1 - 2005/7/20

N2 - Thin films of Cu-phthalocyanine (CuPc), perylene and 3,4,9,10-perylenetetracarboxylic acid dianhydride (PTCDA) were thermally deposited in situ in UHV on ZnO(000-1) surface. The surface potential, the surface work function Phi and the structure of density of unoccupied electron states (DOUS) located 5-25 eV above the Fermi level (E-F) were monitored during the film deposition, using an incident beam of low-energy electrons according to the total current electron spectroscopy (TCS) method. Auger electron spectroscopy (AES) was used to monitor atomic composition of the surfaces under study. The deposition of the perylene and PTCDA films resulted in formation of the DOUS structure typical for these films while the deposition of CuPc films of less than 2 nm thickness resulted in formation of an intermediate DOUS structure which was replaced by a stable DOUS of CuPc along with a further increase of the deposit thickness. Migration of the substrate atoms into the intermediate layer was observed. The electronic work function Phi of the organic films changed during the film deposition until it reached stable values at a film thickness of 810 nm. Width of the interface dipole charge transfer layer and formation of intermediate TCS spectra during the film deposition are selected as relevant parameters for further comparison of the features of the interfaces studied. (c) 2005 Published by Elsevier B.V.

AB - Thin films of Cu-phthalocyanine (CuPc), perylene and 3,4,9,10-perylenetetracarboxylic acid dianhydride (PTCDA) were thermally deposited in situ in UHV on ZnO(000-1) surface. The surface potential, the surface work function Phi and the structure of density of unoccupied electron states (DOUS) located 5-25 eV above the Fermi level (E-F) were monitored during the film deposition, using an incident beam of low-energy electrons according to the total current electron spectroscopy (TCS) method. Auger electron spectroscopy (AES) was used to monitor atomic composition of the surfaces under study. The deposition of the perylene and PTCDA films resulted in formation of the DOUS structure typical for these films while the deposition of CuPc films of less than 2 nm thickness resulted in formation of an intermediate DOUS structure which was replaced by a stable DOUS of CuPc along with a further increase of the deposit thickness. Migration of the substrate atoms into the intermediate layer was observed. The electronic work function Phi of the organic films changed during the film deposition until it reached stable values at a film thickness of 810 nm. Width of the interface dipole charge transfer layer and formation of intermediate TCS spectra during the film deposition are selected as relevant parameters for further comparison of the features of the interfaces studied. (c) 2005 Published by Elsevier B.V.

KW - surface electronic phenomena

KW - metal oxide surfaces

KW - conjugated organic molecules

KW - inorganic-organic semiconductor interfaces

KW - ZnO

KW - ENERGY-LEVEL ALIGNMENT

KW - INTERFACE FORMATION

KW - FILMS

KW - PHTHALOCYANINES

KW - DEVICES

U2 - 10.1016/j.susc.2005.05.006

DO - 10.1016/j.susc.2005.05.006

M3 - статья

VL - 586

SP - 129

EP - 136

JO - Surface Science

JF - Surface Science

SN - 0039-6028

IS - 1-3

ER -