The production and use of semiconducting nanopost arrays made by nanofabrication is described herein. These nanopost arrays (NAPA) provide improved laser ionization yields and controllable fragmentation with switching or modulation capabilities for mass spectrometric detection and identification of samples deposited on them.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 This invention was made with government support under grant number DEFG02-01ER15129 from the Department of Energy. The U.S. Government has certain rights in this invention.