Optical absorption and electron-nuclear double resonance study of Ni⁺ions in AgGaSe₂crystals

Abstract

Optical absorption, electron paramagnetic resonance (EPR) and electronnuclear double resonance (ENDOR) have been used to characterize Ni + ions substituting for Ag + ions in AgGaSe 2 crystals. These Ni + ions are responsible for a strongly polarized optical absorption band peaking near 2.2 µm (the maximum absorption occurs with E c). Phonon structure is resolved at low temperature. This infrared band, which is present even in undoped crystals because of trace amounts of Ni, can significantly degrade the performance of optical parametric oscillators using AgGaSe 2 . Sets of EPR and ENDOR angular dependence data were taken in the (010), ( 110) and ( 001) planes. This allowed the g matrix, the 61 Ni hyperfine and nuclear quadrupole matrices, the 77 Se hyperfine matrix for the four nearest neighbours and the 69,71 Ga hyperfine and nuclear quadrupole matrices for four neighbours to be determined. Of the eight gallium near neighbours, only the four in the basal plane containing the Ni + ion have a significant interaction. Large hyperfine interactions with 107,109 Ag nuclei were not observed.

Green luminescence from Cu-diffused LiGaO2 crystals

“…Following the earlier work on 3d 9 ions in tetrahedrally bonded ZnO, GaN, and AgGaSe 2 [19][20][21], we suggest that the unpaired spin in the Cu 2+ ion in LiGaO 2 occupies an xy-like orbital.…”

An EPR and ENDOR Investigation of a Series of Diazabutadiene–Group 13 Complexes

“…These unusual EPR features appear to be accompanied by unusual ENDOR features (i.e., the appearance of new resonances from 20-55 MHz) which we assign to 69,71 Ga couplings. While gallium ENDOR signals have been widely reported in doped semiconductor systems, [25] this is to the best of our knowledge the first observation of gallium ENDOR signals in any discrete molecular metal complex system.…”

EPR g factors and tetragonal distortion for the isoelectronic Ni+ and Cu2+ centers in the CuGaSe2 crystal

“…The estimation is based on the relation DqpR À n (where n E571.5 [26,27]). From the DqE380 cm À 1 for similar (NiSe 4 ) 7 À cluster in AgGaSe 2 [28] crystal. Thus, we obtain for Cu 2 + in CuGaSe 2 , DqE700 cm À 1 .…”