Functional carbon nanomembrane : microfabrication and functionalization Carbon nanomembranes (CNMs) are fabricated via cross linking the aromatic self assembled monolayers (SAMs) with low energy electron irradiation. As the first reported organic 2D material CNMs possess numerous special properties such as ultimate thinness high mechanical stability high tunnelling resistance homogeneous porosity adjustable chemical functionality and high transmittance to light. This thesis demonstrates the electrochemical delamination (ECD) assisted transfer and the chemical functionalization of CNMs and their applications in different fields including selective ion sieving fabricating optical metasurfaces immobilizing biospecimens for cryogenic electron microscopy (cyroEM) imaging and building photo switchable graphene field effect transistor (GFET). The properties of the fabricated CNMs and CNMs based materials (or devices) were characterized employing complementary methods such as transmission electron microscopy (TEM) X ray photoelectron spectroscopy (XPS) Raman spectroscopy atomic force microscopy (AFM) as well as surface plasmon resonance (SPR) measurements etc.