Surface Microscopy of Atomic and Molecular Hydrogen from Field-Evaporating Semiconductors

We report on the microscopic behavior of residual hydrogen nanometric field emitters. By using homogeneous or heterostructured semiconductor specimens analyzed in a laser-assisted atom probe, it is possible to study how relative abundances ionic species H+, H2+, and H3+ depend electric field, estimated through post-ionization statistics. In case Ga-containing semiconductors, follow common trend, independent nonmetallic component matrix. The dependence total H flux exhibits more complex behavior, which depends also spatial direction variation (in-depth on-surface). analysis multiple detection events provides further insights into surface chemistry. Noticeably, H+–H3+ ion pairs are both correlated number separated by very small distances detector space, suggesting reaction 2H2 → H3++H++2e– taking place emitter surface.