Optimization of trade-off between mobile carriers and surface defects for enhanced H2S sensing in SnO2-decorated In2O3 nanocomposites via two-step temperature and pressure control

초록

SnO2-decorated In2O3 nanocomposites that feature nanoleaf-like SnO2 grown on In2O3 nanocubes via a surface-wrapping mechanism were synthesized using two consecutive hydrothermal methods. These samples exhibited an unusual temperature-dependent response to H2S gas (150 degrees C > 200 degrees C > 100 degrees C > 250 degrees C), which contrasts with the typical behavior of semiconductor gas sensors. This nonlinear trend is attributed to the dominance of different sensing mechanisms: an oxygen vacancy-controlled mode between 100 and 150 degrees C and a majority carrier-controlled mode between 200 and 250 degrees C. The results highlight the importance of balancing the trade-off between operating temperature and surface-defect concentration to enhance gas sensing.

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