Production and electrical characterization of PTCDI-C8/P-Si hybrid organic/inorganic heterojunction diode

PTCDI-C8 is a very important organic material for electronic and optoelectronic devices with high mobility, n-type semiconductor properties. The widespread use of organic-inorganic hybrid devices has made it important to use organic molecule semiconductors in different optoelectronic devices and to reveal their electrical properties. In this work, PTCDI-C8/p-Si heterojunction was formed by growing a thin film of PTCDI-C8 semiconductor organic molecule on p-type silicon by sol-gel spin coating technique. For comparison, p-Si/Al metal-semiconductor (MS) diode without interlayer was also produced under the same conditions. Electrical properties of PTCDI-C8/p-Si/Al heterojunction and p-Si/Al MS diode were investigated by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. Both junctions showed good rectifying properties. The ideality factor (2.1), barrier height (0.74 eV) and series resistance (248 kΩ) of the PTCDI-C8/p-Si/Al heterojunction were obtained from I–V characteristics. The barrier height obtained for the PTCDI-C8/p-Si/Al heterojunction is higher than that of obtained for the conventional Al/p-Si Schottky diode. PTCDI-C8 organic thin film layer formed a physical barrier between Al metal and p-Si, modifying the effective barrier height of the Al/p-Si Schottky diode. The photovoltaic parameters of the device have been also determined under 100 mW/cm2 and AM1.5 illumination condition. The PTCDI-C8/p-Si/Alg heterojunction exhibits a photodiode behavior with open circuit voltage (Voc = 320 mV) and short circuit current (Isc = 1.91 µA).