Temperature dependent charge-injection at the metal-organic semiconductor interface and density of states in pristine and doped pentacene

Applied Physics Letters

Volumn 94, Issue 25, 2009, Pages

  Vanoni, Claudio ^a   Jung, Thomas A ^a   Tsujino, Soichiro ^a  

^a PAUL SCHERRER INSTITUTE   (Switzerland)

Author keywords

[No Author keywords available]

Indexed keywords

CARRIER INJECTION; DENSITY OF STATE; ELECTRICAL TRANSPORT; F4-TCNQ; HOLE INJECTION BARRIERS; METAL-ORGANIC SEMICONDUCTOR INTERFACES; PENTACENE; PENTACENE INTERFACE; PHYSICAL MECHANISM; TEMPERATURE DEPENDENT; TETRAFLUORO-TETRACYANOQUINODIMETHANE;

DOPING (ADDITIVES); SURFACE CHEMISTRY; THIN FILM TRANSISTORS;

SEMICONDUCTING ORGANIC COMPOUNDS;

EID: 67649494448     PISSN: 00036951     EISSN: None     Source Type: Journal    
DOI: 10.1063/1.3159835     Document Type: Article

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24. Here, pac was evaluated from the positive threshold gate voltage shift of ∼1 V of the doped-PC TFT compared to the pristine-PC TFT at room temperature. The total concentration of the F4 TCNQ molecules co-deposited in the PC film is equal to ∼4× 1019 cm-3. Therefore, the fraction of the electronically active F4 TCNQ is in the order of 10-2. Previous estimates of the doping efficiency of F4 TCNQ molecule to PC returned a value equal to ∼0.1 holes/dopant in vacuum. The lower doping efficiency by a factor of about 10 observed here, is ascribed to the brief (∼5 min) exposure of the sample to the ambient air during the transfer from the PC deposition chamber to the cryostat (see also Ref.).
25. The doping-induced states observed here is potentially consistent with the previously observed Vg -dependence of Rc in TFTs (Ref.); An increase of Rc upon increasing the negative Vg above 10 V can be ascribed to the resonantlike-injection from Au into the doping-induced states detuned by Vg.