Influence of Hydrogenation on Electrical Conduction in HgCdTe Thin Films on Silicon

HgCdTe is the standard state-of-the-art infrared detector material for space applications. HgCdTe-based infrared photon detector performance can be hindered due to the presence of bulk crystal defects and dangling bonds at surfaces or interfaces. Passivation of such bulk defects and surfaces can potentially improve detector performance by saturating dangling bonds in dislocation cores and at surfaces. Indeed, results showing improvement of HgCdTe current-voltage characteristics after hydrogenation have been reported. Here we use multiple-carrier fitting of Hall-effect data, acquired under variable magnetic field strengths and sample temperatures, to investigate the physical influence of hydrogenation, as a passivation procedure, on HgCdTe crystalline thin films on Si(211) substrates. We find: (1) evidence of multiple active electrical carrier species in all samples, (2) evidence of surface electrical conduction before and after hydrogenation, and (3) changes in carrier concentration and mobility induced by hydrogenation.