Improved electrical stability of CdS thin film transistors through Hydrogen-based thermal treatments
AuthorsSalas Villaseñor, Ana L.
Mejia, Israel I.
Alshareef, Husam N.
Quevedo-López, Manuel Angel Quevedo
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
Functional Nanomaterials and Devices Research Group
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AbstractThin film transistors (TFTs) with a bottom-gate configuration were fabricated using a photolithography process with chemically bath deposited (CBD) cadmium sulfide (CdS) films as the active channel. Thermal annealing in hydrogen was used to improve electrical stability and performance of the resulting CdS TFTs. Hydrogen thermal treatments results in significant V T instability (V T shift) improvement while increasing the I on/I off ratio without degrading carrier mobility. It is demonstrated that after annealing V T shift and I on/I off improves from 10 V to 4.6 V and from 105 to 10 9, respectively. Carrier mobility remains in the order of 14.5 cm2 V s-1. The reduced V T shift and performance is attributed to a reduction in oxygen species in the CdS after hydrogen annealing, as evaluated by Fourier transform infrared spectroscopy (FTIR). © 2014 IOP Publishing Ltd.
SponsorsAuthors would like to thank CONACyT project 158281, The AFOSR project FA9550-10-1-0183, and COSMOS for partially supporting this work.