Current–voltage characteristics of Al/Rhodamine-101/n-GaAs and Cu/Rhodamine-101/n-GaAs rectifier contacts

The organic compound Rhodamine-101 (Rh101) film on an n-type GaAs substrate with carrier concentration of 7.3 × 1015 cm−3 has been formed by means of the evaporation process, and thus Al/Rh101/n-GaAs and Cu/Rh101/n-GaAs contacts have been fabricated. Our aim is to realize a modification of Schottky barrier height (SBH) of the devices using a thin non-polymeric organic compound layer. The Al/Rh101/n-GaAs and Cu/Rh101/n-GaAs contacts have behaved like rectifying contact with the SBH values of 0.68 eV and 0.72 eV, and with ideality factor values of 2.61 and 2.60 obtained from their forward bias current–voltage (I–V) characteristics at the room temperature, respectively. It has seen that the SBH values obtained for these devices are significantly different from those obtained for the conventional Al/n-GaAs or Cu/n-GaAs Schottky diodes. Furthermore, it has been demonstrated that the trapped-charge-limited current is the dominant transport mechanism at large forward bias voltage.