Different semiconducting types are applied in various fields of the semiconductor industry: organic, inorganic and hybrid. Each of these semiconducting types of materials have their own strengths as well as their weakness. Inorganic materials possess low absorption and high carrier mobility while organic materials possess high absorption and low carrier mobility. Inorganic/organic hybrid semiconducting devices take advantage of the mixing of these two types of semiconductors. By building a heterojunction with inorganic and organic materials, the advantages of each individual material is passes onto this new hybrid while cancelling out the disadvantages. In this master thesis, the fabrication procedure and characterization techniques are studied for inorganic, organic and hybrid semiconducting devices. For the inorganic materials, fabrication was performed in the MicroFabrication Facility in order to properly achieve small features in the micrometer range. Device processing was performed to achieve a high-electron mobility transistor using AlGaN/GaN and AlInN/GaN heterostructures. The fabrication procedure involved the defining of features through photolithography, ion mill etching, and electron-beam evaporation. Electrical characterization was performed on both heterostructures to make a comparison. The organic device studied was a photoconductor using the conducting polymer P3HT and an optical and electro-optic comparison was made with the addition of MWCNT into the polymer matrix. A hybrid pn-junction diode was fabricated using P3HT and electrical measurements were performed and analyzed through an equivalent circuit to characterize and compare it to a P3HT:MWCNT active layer for the pn-junction.