"Dip-Pen" nanolithography on semiconductor surfaces

Dip-Pen Nanolithography (DPN) uses an AFM tip to deposit organic molecules through a meniscus onto an underlying substrate under ambient conditions. T hus far, the methodology has been developed exclusively for gold using alky l or aryl thiols as inks. This study describes the first application of DPN to write organic patterns with sub-100 nm dimensions directly onto two dif ferent semiconductor surfaces: silicon and gallium arsenide. Using hexameth yldisilazane (HMDS) as the ink in the DPN procedure, we were able to utiliz e lateral force microscopy (LFM) images to differentiate between oxidized s emiconductor surfaces and patterned areas with deposited monolayers of HMDS . The choice of the silazane ink is a critical component of the process sin ce adsorbates such as trichlorosilanes are incompatible with the water meni scus and polymerize during ink deposition. This work provides insight into additional factors, such as temperature and adsorbate reactivity, that cont rol the rate of the DPN process and paves the way for researchers to interf ace organic and biological structures generated via DPN with electronically important semiconductor substrates.