Emitter life and emission stability of held emission Vacuum microelectronic devices are strongly influenced by the morphology and surface chemistry of the emission surfaces. Vacuum microelectronic devices like field emission displays. (FEDs) are vacuum devices, which have continuous interaction between the emission surfaces and the residual gases in the vacuum envelope. Any significant variation in the shape, morphology, or chemical composition of the emitter surface will result in emission current changes. In this article, we report measurements of the surface chemical modifications of active FED cathodes due to their interaction with the residual gas environment within the vacuum envelope. The changes in emitter tip height is measured using high resolution scanning electron microscopy (SEM). Surface chemical changes are determined by micro-Auger electron spectroscopy and x-ray photoelectron spectroscopy (XPS). Observations with SEM did not show any measurable changes in the tip height and shape. The micro-Auger and XPS measurements indicate the accumulation of surface oxides on tips that have undergone aging.