methods for covalently modifying surfaces of various substrates are disclosed , along with various substrates having surfaces modified by such methods . candidate surfaces include various polymeric , siliceous , metallic , allotrophic forms of carbon , and semiconductor surfaces . the surfaces are exposed to a reagent , having molecules each comprising a nitrenogenic group and a functionalizing group , in the presence of energized charged particles such as electrons and ions , photons , or heat , which transform the nitrenogenic reagent to a nitrene intermediate . the nitrene covalently reacts with any of various chemical groups present on the substrate surface , thereby effecting nitrene addition of the functionalizing groups to the substrate surface . the functionalizing groups can then participate in downstream chemistry whereby any of a large variety of functional groups , including biological molecules , can be covalently bonded to the surface , thereby dramatically altering the chemical behavior of the surface . such functionalizations of the surface can be done in a single reactive step or in multiple reactive steps .