The realization of fast, robust and low-power integrated circuits on plastic foil are hard to achieve with today's unipolar (p-type only) organic thin-film technology. Only a technology of complementary logic at low temperatures can result in a further breakthrough.Owing to the electronic structure and ionic bonding nature, n-type metal-oxides (such as ZnO, In2O3, and InGaZnO) have unique properties such as large bandgaps, wide controllability of carrier concentration, and great flexibility in impurity doping while still retaining reasonably high carrier mobility.Compared to organic n-type semiconductors, higher mobilities and better stability are achieved with metal-oxide semiconductors. Therefore, the most realistic approach for complementary logic is the integration of organic p-type and metal-oxide n-type thin-film transistors. Combining both types of transistors on plastic foil with reasonable performance and high density in one single technology was the main goal of this Ph.D. Two generations hybrid oxide-organic complementary technologies have been developed, respectively on PI and PEN foil, based on solution-processed oxide n-type and organic p-type transistors. The process temperature was limited to 150 - 250C and finally resulted in a few complex digital circuit demonstrators such as a 96-bit RFID transponder chip on PEN foil, operating at 13.56 MHz with bi-directional communication, and a 8-bit thin-film microprocessor with print-programmable read-only memory, comprising of 4356 transistors. To date, only a limited amount of candidate p-type oxide semiconductors have been identified. In this work, we showed that high performance p-type tin monoxide (SnO) TFTs could be obtained by thermal vacuum evaporation. This broadens the view on complementary thin-film logic towards fully oxide-oxide integration schemes.The understanding of charge tranport in metal-oxide TFTs is of primary importance in the evolution towards more stable and higher performance devices. The temperature dependence of transistor mobility was therefore studied for both n- and p-type oxide TFTs. We obtained a better insight in the conduction mechanisms and found one single measure to judge the quality of disordered solution-based n-type oxides, being the Meyer-Neldel temperature. In addition we derived the density of localized tail states distribution in p-type SnO, based on an analytical model for hopping transport and Hall effect measurements.