Rubrene thin-film transistors with crystalline and amorphous channels

The authors report on the fabrication of rubrene organic thin-film transistors (OTFTs) with crystalline and amorphous channels, which were achieved by patterning a rubrene thin film deposited under a specific condition. The deposited film was mostly covered by amorphous rubrene matrix with smooth surface except many crystalline rubrene disks embedded with rough surface. When the channel of OTFT covers some portion of crystalline disks, the OTFT displayed a typical field effect behavior while it showed little drain current with the channel covered with amorphous background. Typical field mobility obtained from OTFT with crystalline disks was 1.23×10−4cm2∕Vs with an on/off current ratio of ∼103.