Covalent molecular functionalization of diamond thin-film transistors

The chemical functionalization and the resulting electrical properties of diamond thin-film transistors (TFTs) modified with organic monolayer films have been explored. Chemical processing steps were developed to produce amine-terminated surfaces in a manner compatible with pre-existing front-surface metal contacts and dielectric protecting layers. The electrical properties of the monolayer-modified TFTs fabricated using different procedures were investigated. Interchanging the order of the functionalization and contact deposition steps changes the devices transconductance by a factor of 100. Electrical measurements of thin-film transistor devices with three different molecular terminating groups show significant changes in threshold voltage that correspond with the expected charges of the functional groups.