A high sensitive chemiresistive-biosensor based on self-assembly grown GaN porous layer

As 3rd generation semiconductor, GaN material is promising for biosensor application, owing to its excellent chemical stability and high carrier mobility. Herein, GaN porous-layer (GNP) was self-assembly grown on GaN-coated sapphire substrate without doping by using simple low-temperature (LT) growth. The GNP with a pore density as high as ∼2.1 × 10 3 μm −2 can be realized by optimizing the growth temperature (620 °C) and layer thickness (22.4 nm), and its normalized conductivity can be tuned by simply changing the thickness. The optimized GNP was applied to chemiresistive detection of Cu 2+ with a limit of detection (LOD) as low as 8 fM, a fast response speed of 1.5 min, a wide linear range (8 fM∼8 nM) and good repeatability. The LOD was improved 1.25∼10 6 fold compared with that of previously reported biosensor. The GNP biosensor features high sensitivity, simple structure, integratability, and low-cost. To our knowledge, it is the first time that GaN material was used for chemiresistive biosensor.