Fabrication of Diamond AFM Tips for Quantum Sensing

摘要

Diamond attracts an ever-increasing scientific interest not only due to its outstanding properties, but also as host material for the so-called color centers. In particular, the nitrogen-vacancy (NV) center is a promising candidate for applications in quantum sensing on a nanoscale. Incorporating such centers in sharp diamond tips, allows the fabrication of a controllable sensor for magnetic and electric fields. In this regard, we present two different ways to fabricate diamond atomic force microscope (AFM) probes. One approach is based on a bottom-up method, first structuring a silicon substrate by photolithography and anisotropic wet etching and subsequently depositing a nanocrystalline diamond (NCD) film onto the pre-patterned silicon substrate. The second approach is based on electron beam lithography (EBL) and reactive ion etching (RIE), which is also applicable to monocrystalline diamond (MCD). To this end we show our first results in fabricating NV-containing MCD tips by He~+ ion implantation and annealing. We demonstrate the fabrication of bottom-up NCD probes with tip radii in the range of ca. 25 nm, and top-down fabricated NCD AFM probes with tip radii even below 10 nm.