4. Conclusions
We have shown that DNA can be directly immobilized onto ZrO2, AlGaN, GaN, and HfO2 in a phosphate dependent manner. Immobilization was not successful for SiO2 or TiO2 surfaces, although alternative deposition methods could yield successful DNA immobilization on these materials. The primary application of this immobilization technique is for electrical-based nucleic acid detection systems, such as field-effect transistors (FETs) and high electron mobility transistors (HEMTs) that utilize these materials for active device components such as gate oxides/dielectrics. In each case, nucleic acid probes can be directly immobilized onto the substrates tested without complex surface chemistry, cross-linking, or probe modifications.