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We have developed a general and low-cost, solution-based process that is suitable for the deposition of transparent conducting oxides through spin-coating or inkjet printing under ambient conditions. Highly transparent (-95% in the visible portion) zinc tin oxide semiconducting thin films were deposited by spin coating. The deposited films were found to be smooth and uniform with an amorphous structure. Enhancement-mode metal-insulator-semiconductor field-effect transistors were fabricated showing a field-effect mobility (μ FE ) as high as 16 cm 2 /V s, a turn-on voltage of 2 V, a current on-to-off ratio greater than 10 5 , and a high on-current of 2.25 mA.

The highly transparent SnO 2 thin films were deposited through solution-based inkjet printing using a simple precursor solution. We were able to fabricate porous tin oxide thin film that has a thin nanoporous layer on top and a thicker meso- and macroporous layer beneath the top layer. The thin-film transmittance is over 98% in the visible wavelength range. A mechanism based on gas evolution was proposed to explain the formation of porous structure. A depletion-mode thin-film transistor using the porous tin oxide channel layer was fabricated with a field-effect mobility of 3.62 cm 2 /V s.

In this work, we developed a continuous flow microreactor that is capable of overcoming the drawbacks associated with chemical bath deposition. Uniform, smooth, and highly oriented nanocrystalline CdS semiconductor thin films were successfully deposited on oxidized silicon substrates at low temperature (80°C) using this microreactor. Functional thin-film transistors with an effective mobility of 1.46 cm 2 /V s were fabricated from the as-deposited films without any postannealing process. This process is a potentially low-cost avenue for the fabrication of thin-film electronics on flexible polymeric substrates.

Ni-mediated crystallization of amorphous silicon (a-Si) with a SiO 2 nanocap layer formed by O 2 plasma treatment was studied. An ultrathin Ni layer was deposited on the nanocap and then this was annealed in a UV heating system. The Ni atoms in a-Si films, diffused through the nanocap, formed NiSi 2 crystallites acting as nuclei. Then, disk-shaped grains were grown from the nuclei. The grain size increased from ∼4 to ∼28 μm as the SiO 2 thickness changed from 2.4 to 3.2 nm. The use of a nanocap gave an increased grain size and improved material property.

In this work, chemical bath deposition (CBD) of CdS was monitored using a quartz crystal microbalance as a function of time, temperature, reactant concentration (ex situ atomic absorption measurement), and pH level. It is found that the reaction could be limited by mass transport at certain concentrations and temperatures. The measurements also indicate the total Cd concentration in the solution changes dramatically in the linear growth regime with a constant deposition rate. One possible explanation is that the linear growth regime is actually a combination of molecule-by-molecule growth and cluster-by-cluster growth mode. This hypothesis is further supported by real time dynamic light scattering and transmission electron microscopy measurements.