The Behaviour of the Hydrogen‐Localized Vibrational Mode in Proton‐Implanted GaAs

Abstract

A hydrogen-induced infrared absorption band located around 1835.4 cm-' is observed in protonimplanted GaAs single crystal at 4.2 K and identified as a hydrogen localized vibrational mode (LVM). The dependence of absorption intensity, linewidth, and frequency of the hydrogen LVM on temperature is presented for the first time. Both, the linewidth and frequency shift due to temperature variation are much larger than those of the hydrogen-

Unstable displacement defects and hydrogen trapping in GaAs

“…The As sublattice defect assignments were made in deep-level transient spectroscopy ͑DLTS͒ studies, 23 and the Ga-H centers observed in infrared absorption studies have been attributed to hydrogen bonded to Ga atom neighbors of displaced As atoms. 8 We suggest that displacements on the Ga sublattice and multiple displacements in hydrogen implantation at 80 K create strain conditions and defects favorable for the formation of As-H centers. The release of hydrogen from bonds in these centers is attributed to annealing of defects that created the conditions favorable for formation of As-H bonds.…”

“…2,[6][7][8] The 2029 cm Ϫ1 in hydrogen-implanted GaAs has been assigned to a stretch mode for As-H bonds. 15 Assignments for the Ga-H and As-H bands are firmly based upon frequency shifts produced by hydrogen isotope substitution, upon substitution of the group III and group V constituents ͑e.g., InAs and InP substituted for the GaAs host 15 ͒, and upon correspondence of the observed frequencies to those for Ga-H and As-H bonds in solids.…”

“…In Si, for example, the annealing characteristics for an Si-H center produced by hydrogen implantation near 100 K were shown to correlate 21 with those for vacancies identified and characterized in EPR studies. 22 Previous studies on GaAs following hydrogen implantation at room temperature [6][7][8] have shown that annealing of Ga-H centers correlates with annealing of vacancy-interstitial pairs (V As -As i ) or V As defects produced on the As sublattice. The As sublattice defect assignments were made in deep-level transient spectroscopy ͑DLTS͒ studies, 23 and the Ga-H centers observed in infrared absorption studies have been attributed to hydrogen bonded to Ga atom neighbors of displaced As atoms.…”

“…1,3 Implantation of GaAs with hydrogen at room temperature produces a LVM for Ga-H bonds detected by IR absorption. 1, [6][7][8] It is widely accepted that these bonds form at As vacancy (V As ) or Frenkel pair (V As -As i ) displacement defects on the As sublattice. 1,6-8 It is known from irradiation damage studies on GaAs, however, that significant defect annealing can occur below room temperature [9][10][11][12] so that the Ga-H centers may not be the initial bonding site for hydrogen.…”

Local polariton states in polar crystals with impurities

“…First, they become quasistationary with a finite lifetime. This time, however, is usually several orders of magnitude greater then the oscillation period of local modes (e.g., for hydrogen-localized vibrational modes in GaAs this ratio is ∼ 10 3 [16]). Since the relaxation of local polaritons is mainly determined by the decay of phonon or exciton components, one can expect their lifetime to be approximately of the same order of magnitude.…”