The team of Prof. Huang Hui at Dalian University of Technology invented a technology of “leakage-free bridge growth of nanowires”. Based on this technology, a GaN nanowire gas-sensor of high stability (variation in resistance of <0.8% during 240 days), high sensitivity (detection of 0.5 ppb NO2), and low power consumption (capable of room-temperature operation) was realized. The experimental result was published in "Nano Letters".
At present, semiconductor integrated circuit (IC) has developed rapidly. If IC is recognized as human brain, sensors can be considered as human sensory organs. Thus, IC and sensors are interdependent. However, the development of sensors (especially integrated nanosensor) lags far behind the development of IC.
For the first time, the team of Prof. Huang investigated the parasitic deposition in bridging growth, and invented a growth method which combines shadowing effect with the surface-passivation effect to eliminating the parasitic deposition. Then, an integrated gas sensor based on bridging GaN nanowire was realized, which features high stability, low power consumption and high sensitivity and can resolve the problems encountered in nanowire device fabrication, such as nanowire assembly, electrode contact and material stability. GaN is the third generation of semiconductor materials suitable for applications in environments of high temperature, oxidation, and corrosion and biological compatibility. Thus, the GaN nanowire sensor can be used for detecting stress/strain, liquid and gas samples under harsh environment (it has been proved that 48 hours hydrofluoric corrosion dose not degrades the GaN nanowires).