Abstract
Bulk single crystals up to 20 mm in diameter and 40 mm long for LiInS2 end up to 10 mm, 20 mm, respectively, for LiInSe2 have been grown. Their colour changed from colourless to rose for the first one and from yellow to dark red for the other. All crystals have wurtzite-type lattice (Pna21 space group), lattice parameters were determined. A band gap was found tobe 3.72 and 357 eV for LiInS2 and 3.02, 2.86 eV for LiInSe2 at 80 and 300 K, respectively. Colour variations are due to point defects, first of all to interstitial sulfur, resulting in additional wide absorption bands in the shortwave part of transparency range. For LiInS2 the SHG phase matching conditions were found to be similar for samples of different colour and some difference from Boyd's predictions of 1973 was shown: for XY plane Δφ≃ +3° at 2.6 μm and Δφ∼ -3 to -5° at 4-5 μm. Nonlinear susceptibility for LiInS2 was estimated: deff(XY) ∼3.4 pm/V relative to Boyd's value as 10.6 pm/V. A proper illumination gives a photoinduced change of LiInSe2 colour from dark red to yellow as a result of changes in point defects charge state.
Original language | English |
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Pages (from-to) | 135-141 |
Number of pages | 7 |
Journal | Opto-electronics Review |
Volume | 9 |
Issue number | 2 |
Publication status | Published - Jan 1 2001 |
Externally published | Yes |
Keywords
- Absorption
- Band gap
- Colour
- Lattice parameters
- Lithium indium sulfide/selenide
- Nonlinear susceptibility
ASJC Scopus subject areas
- Radiation
- Materials Science(all)
- Electrical and Electronic Engineering