摘要
AlGaNGaN high electron mobility transistors (HEMTs) functionalized with polyethylenimine/starch were used for detecting CO 2 with a wide dynamic range of 0.9%-50% balanced with nitrogen at temperatures from 46 to 220 °C. Higher detection sensitivity to CO 2 gas was achieved at higher testing temperatures. At a fixed source-drain bias voltage of 0.5 V, drain-source current of the functionalized HEMTs showed a sublinear correlation upon exposure to different CO 2 concentrations at low temperature. The superlinear relationship was at high temperature. The sensor exhibited a reversible behavior and a repeatable current change of 32 and 47 μA with the introduction of 28.57% and 37.5% CO 2 at 108 °C, respectively. © 2008 American Institute of Physics.