DNA Immobilization on GaP(100) Investigated by Kelvin Probe Force Microscopy

Understanding changes in the properties of semiconductor materials after immobilization of biomolecules on the surface is essential for the fabrication of well-tuned and programmable devices. The work examines changes in the properties of gallium phosphide (GaP) after modification with an organic linker, a single stranded DNA, and its complementary strand. We investigated changes in surface potential with Kelvin probe force microscopy (KPFM). Analysis revealed that a more ordered adlayer of ssDNA was present when a lower concentration of linker molecule was used. KPFM data combined with coverage data obtained from X-ray photoelectron spectroscopy (XPS) further confirmed this result. Successful hybridization with the complementary strand was confirmed by both KPFM and Raman spectroscopy. The results indicate that one can control the amount of DNA on the surface by changing the initial concentration of the organic linker, and thus modulate the surface potential of the semiconductor material.

理解在生物分子固定于表面后半导体材料性质的变化对于制造性能良好且可编程的器件至关重要。这项工作研究了用一种有机连接分子、单链DNA及其互补链修饰后磷化镓（GaP）性质的变化。我们用开尔文探针力显微镜（KPFM）研究了表面电位的变化。分析表明，当使用较低浓度的连接分子时，会出现更有序的单链DNA吸附层。KPFM数据结合从X射线光电子能谱（XPS）获得的覆盖度数据进一步证实了这一结果。通过KPFM和拉曼光谱都证实了与互补链的成功杂交。结果表明，可以通过改变有机连接分子的初始浓度来控制表面上DNA的量，从而调节半导体材料的表面电位。