Birefringence in CdSiP₂

Growth and characterization of large CdSiP2 single crystals

“…CdSiP 2 is a negative uniaxial II-IV-V 2 chalcopyrite compound semiconductor (space group 42 m) with a reported band gap of 2.45 eV (506 nm) [2] that allows 1064 nm pumping without twophoton absorption, and is transparent out to 9 mm. The refractive index is very close to 3.0 throughout most of its transparency range, and its birefringence of À0.05 is large enough for phase matching 1, 1.5, and 2 mm lasers into the mid-infrared.…”

“…Although the value of the birefringence was determined in this calculation, the sign of birefringence could not be determined by this route. The sign of the birefringence was determined to be negative both in previous measurements [2] and through the Sellmeir equations described in the next section. The resulting birefringence versus wavelength plot is shown in Fig.…”

“…They can, however, be plagued by defect related absorption losses near the band edge when grown from the melt, but these can often be eliminated by post-growth processing. CdSiP 2 is a II-IV-V 2 compound that has been examined by several authors starting in the late 1960s [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Borshchevskii et al [5] reported halogen assisted vapor transport growth of the compound as early as 1967, and Spring-Thorpe and Pamplin [4] reported growth from molten tin solution in 1968.…”

“…A detailed analysis of the crystal structure was reported by Abrahams and Bernstein [1], placing the crystal in the tetragonal space group 42 m, with the lattice parameters of a = 5.68Å and c= 10.431Å. Several authors [2,4,8] reported that the band gap is approximately 2.2 eV (560 nm). The birefringence of tiny 2 Â 2 Â 0.2 mm 3 CdSiP 2 crystals grown from a molten tin flux was measured by Itoh et al [2] and found to be À 0.045 at 840 nm.…”

“…Several authors [2,4,8] reported that the band gap is approximately 2.2 eV (560 nm). The birefringence of tiny 2 Â 2 Â 0.2 mm 3 CdSiP 2 crystals grown from a molten tin flux was measured by Itoh et al [2] and found to be À 0.045 at 840 nm. More recent studies examined the cathodoluminescence [11] and nuclear magnetic resonance (NMR) spectra [12] of small CdSiP 2 crystalline samples, and recent theoretical studies examined the calculated electronic band structure [13][14][15][16].…”