@article{xiao_retterer_thomas_tao_he_2009, title={Impacts of Surface Morphology on Ion Desorption and Ionization in Desorption Ionization on Porous Silicon (DIOS) Mass Spectrometry}, volume={113}, ISSN={["1932-7455"]}, DOI={10.1021/jp808844f}, abstractNote={Ordered silicon nanocavity arrays were prepared with e-beam lithography to yield systematically varied pore features and porosity (4−92%). These substrates were used to investigate the effects of substrate morphology on desorption ionization on porous silicon-mass spectrometry (DIOS-MS). Five benzylpyridinium salts, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and angiotensin III were used as the model molecules in the study. For substrates of the same pore depth, MS results suggested that the pore size and the interpore spacing had little impact on the laser irradiation threshold required for ionization. Instead, the laser threshold was found to be highly dependent on the overall porosity for all substrates investigated—the higher the porosity the lower the threshold. Moreover, the substrates with deeper pores but of similar porosity showed significantly reduced laser thresholds. This close relationship between laser threshold and substrate morphology was attributed to the thermal confinement prop...}, number={8}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Xiao, Yongsheng and Retterer, Scott T. and Thomas, Darrell K. and Tao, Jia-Yuan and He, Lin}, year={2009}, month={Feb}, pages={3076–3083} }