CHEMISTRY OF HNO3 ON GE(100)

We describe here the initial bonding geometry and decomposition mechan ism of HNO3 on Ge(100). A combination of high-resolution electron ener gy loss spectroscopy, Auger electron spectroscopy, and temperature pro grammed desorption experiments have been used to shed light on the det ails of this complex but technologically important system. It was foun d that HNO3 adsorbs molecularly at 190 K in a predominantly bidentate bonding configuration. When the substrate is warmed to 425 K, the mole cule decomposes. In a process that involves two adjacent HNO3 adsorbat es, H2O and NO desorb while O remains on the surface. Further heating above 600 K causes the O to desorb as GeO.