Optical-absorption study of hydrogen in Zn-doped Si

摘要

We studied the interaction between hydrogen (H) and Zn or Zn-related defects in Zn-doped Si crystals from the measurements of optical absorption spectra of hydrogen bound to Zn or Zn-related defects. We doped Si crystals with Zn by annealing the crystals in Zn vapor at 1200 deg followed by quenching. After Zn-doping, we doped specimens with H by annealing them in a hydrogen atmosphere followed by quenching. We measured optical abosrption spectra of the above specimens at about 6 K by means of FT-IR spectrometry. Many optical absorption peaks were observed; some are due to electronic transitions and some are due to vibrational transitions of H vibration. Hydrogen atoms are known to passivate Zn acceptors since the optical absorption intensity associated with electronic transitions become much weaker after hydrogenation. Absorption peaks associated with H vibration are known to be related to complexes composed of one Zn atom and two hydrogen atoms. We concluded this from studies on the effect of co-doping with H and deuterium and the efect of Zn isotopes on the optical absorptionspectra due to H.