Enhanced mobility and bias stability of SnO2 thin-film transistors enabled by Ga2O3 passivation-induced two-dimensional electron gas

초록

This study presents a method to achieve both high performance and electrical stability in SnO2 thin-film transistors (TFTs) fabricated by a sol-gel process. Sol-gel-processed Ga2O3 passivation layers are introduced onto the SnO2 active channel layers to address bias instabilities. The Ga2O3 films passivate the back channel by compensating dangling bonds and isolating the channel from H2O and O-2, which improves bias stability. Structural, optical, chemical, and device-level properties were systematically analyzed. When Ga2O3 is deposited on SnO2, electrons redistribute to maintain thermal equilibrium and become confined in the potential well of SnO2, forming a quasi two-dimensional electron gas that increases the free carrier concentration. This effect results in a 1.5-fold enhancement in field-effect mobility (from similar to 10 cm(2)/Vs to similar to 15 cm(2)/Vs) together with improved bias stability. The proposed SnO2-Ga2O3 passivation method offers a promising route toward bias-stable, high-performance metal oxide films for applications in TFTs, solar cells, transparent conducting electrodes, and resistive random-access memory (ReRAM).

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