## 1 Introduction  
Organic semiconductors are one of the most favorable emerging materials for their possible applications in electronic, optoelectronic, thermoelectric, and photonic devices [1; 2; 3; 4; 5]. For instance, these materials have been successfully employed in organic light emitting diodes (OLEDs), organic field effect transistors (OFETs), organic photovoltaics (OPVs), and organic solid-state lasers [6; 7; 8; 9]. Organic semiconductors possess exciting electrical and optoelectronic properties due to its pi (\(\pi\))-conjugated molecular structure that permits the conduction of charge carriers through a hopping process [10]. They offer several distinct properties of their kind, which include mechanical flexibility, solubility in various organic solvents, easy processing for device fabrication (spin coating, drop casting, inkjet printing, etc. ), chemical as well as thermal stabilities, and relatively low-cost, when compared to inorganic semiconductors [11; 12]. In light of the aforementioned properties, it is believed that in near future, organic semiconductors may replace the existing technology of inorganic semiconductors, which are more expensive and require complicated procedures at high temperatures for device fabrication [13]. Organic semiconducting materials can be found either as small molecules, oligomers, or polymers. Particularly, polymeric semiconductors have the advantage that they are generally soluble in different solvents, which makes them suitable for easy device fabrication via spin coating and drop casting. Amongst a large number of semiconducting polymers, poly-(9,9-dioctylfluoremyl-2,7-diyl)-co-(\(N\),\(N\)0-diphenyl)-\(N\),\(N\)'di(p-butyl-oxy-phenyl)-1,4-diamino-benzene) (PFB) is one of the best semiconducting materials that has relatively higher hole mobility due to its large \(\pi\)-conjugated structure, as well as good chemical and thermal stabilities [14]. PFB has found its applications in OLEDs and OPVs due to its high photoluminescence, fluorescence, and strong absorption with broad band in the UV-vis spectrum [15; 16]. However, at the microscopic level, the microelectronic properties of PFB thin films at the junction/interface with other semiconducting materials still need to be studied, understood, and tuned for improvements. Interfaces and junctions between different semiconductors and/or metals play a pivotal role, like a building block in semiconductor devices [17; 18] such as PV cells [19; 20], FET [21], and photo detectors [18]. A hybrid organic-inorganic heterojunction device is fabricated by forming a thin organic semiconductor layer on an inorganic semiconductor, which behaves as a rectifying junction [22]. The structure of the hybrid organic-inorganic heterojunction is of great importance due to the fact that it utilizes the higher charge carrier mobility of an inorganic semiconductor and its solution processing ability, as well as the easy fabrication process of organic semiconductor thin films for device fabrication. These hybrid heterojunctions also provide an excellent platform for wide-range and superior applications by employing desired organic materials that possess interesting optoelectronic properties, remarkable scalability, and high flexibility. Organic materials in heterojunction devices with inorganic semiconductors manifest fabrication at low temperature by simple cost-effective deposition techniques [23]. Although the benefits and significance of organic heterojunction are sufficiently vast, the complete understanding about their properties still remains an issue of discussion. Herein, we study the microelectronic properties of the Ag/PFB/p-Si heterojunction to explore and understand the junction parameters for its potential applications in electronic and optoelectronic devices such as OPVs and organic-inorganic hybrid sensors. Current-voltage (\(I\)-\(V\)) characteristics of the device are studied by using the conventional \(I\)-\(V\) method and Norde's functions for comparison of microelectronic parameters.