Fabrication of polydimethylsiloxane shadow masks for chemical solution deposition of CdS thin-film transistors

PDMS (polydimethylsiloxane) shadow masks were fabricated by replica molding using laser-patterned metal shadow masks as primary templates, which were applied to solution as well as vapor deposition to prepare patterned thin films on solid substrates. We demonstrated a method of fabricating cadmium sulfide (CdS) thin-film transistors (TFTs) using the prepared PDMS shadow masks thanks to their solution-tight, free-standing and elastic characteristics. The patterned CdS thin films were deposited by chemical solution deposition in aqueous solution and aluminum metal electrodes were deposited by thermal evaporation. The electrical characteristics of the CdS/SiO2/n-Si transistors consisted of a field effect mobility of ∼ 0.5 cm2/Vs, a threshold voltage of ∼ 14 V and an on/off ratio of ∼ 107