Field-induced charge transport at the surface of pentacene single crystals: A method to study charge dynamics of two-dimensional electron systems in organic crystals

Abstract

Influence of surface states on the two-dimensional electron gas in AlGaN/GaN heterojunction field-effect transistorsA method has been developed to inject mobile charges at the surface of organic molecular crystals, and the dc transport of field-induced holes has been measured at the surface of pentacene single crystals. To minimize damage to the soft and fragile surface, the crystals are attached to a prefabricated substrate which incorporates a gate dielectric (SiO 2 ) and four probe pads. The surface mobility of the pentacene crystals ranges from 0.1 to 0.5 cm 2 /V s and is nearly temperature independent above ϳ150 K, while it becomes thermally activated at lower temperatures when the induced charges become localized. Ruling out the influence of electric contacts and crystal grain boundaries, the results contribute to the microscopic understanding of trapping and detrapping mechanisms in organic molecular crystals.

Electronic transport properties of pentacene single crystals upon exposure to air

“…Pentacene is a good material for electronic devices like field effect transistors. [1][2][3][4][5][6][7][8] However, the results obtained by different research groups are not always consistent. This can be attributed in part to the fact that the performance of the devices depends critically on the environmental conditions.…”

Organic field-effect transistors using single crystals

“…SC-OFETs were first developed of simple aromatic molecules such as pentacene, tetracene and rubrene [10][11][12][13].…”

“…Both types of devices are described in this review. Organic crystal FETs were prepared either by 'crystallamination' or 'parylene-coating' techniques [10][11][12][13][14]. In the former, thin platelets of single crystals, typically less than 1 µm thick, are grown by physical vapor transport (PVT) and are simply laminated electrostatically on gate-insulating layers.…”

Photoinduced Charge Transfer across the Interface between Organic Molecular Crystals and Polymers

“…To study the charge transfer between an organic semiconductor and a polymer, we have used the field-effect structures based on organic molecular crystals (OMC) [8,9,10,11]. High quality of the OMC surface facilitates fabrication of reproducible and well-characterized interfaces 3 between OMC and a polymer parylene used as the gate dielectric in these devices.…”