Uniform Cr2+ doping of physical vapor transport grown CdSxSe1−x crystals

Abstract

The Cr 2ϩ doped CdS 0.8 Se 0.2 crystals were grown by the vertical, self-seeded, physical vapor transport (PVT) technique. Good quality, crack-and inclusionfree single crystals were grown with an average Cr 2ϩ concentration of 5 ϫ 10 18 cm Ϫ3 . Different source-to-tip distances were used to improve the segregation coefficient (Cr crystal /Cr source ) of the grown crystals. It was observed that lowering the source-to-tip distance increases the segregation coefficient dramatically. With a 2-cm source-to-tip distance, good quality crystals were grown with uniform Cr 2ϩ concentration throughout the ingot. The segregation coefficient was found to be ϳ0.85. The composition of the crystals was also found to be fairly uniform along the length and across the diameter.

Optical and transport properties of chromium-doped CdSe and CdS0.67Se0.33 crystals

“…The Cr 2+ concentration in samples (3-6) is found to vary from 10 17 to 2 Â 10 18 cm À3 . The maximum Cr concentration is close to the Cr concentration in CdS 0.8 Se 0.2 crystals grown by the physical vapor transport technique and doped during crystal growth [12].…”

“…Doping by post-growth in-diffusion is popular for lasing materials preparation, and it has been used for Cr-doping of ZnSe and CdSe crystals [10,11]. However, indiffusion can induce defects resulting from loss of stoichiometry caused by the large difference in vapor pressures of the constituent elements [12]. In the present study, we have employed chromium doping during crystal growth, as in Ref.…”

“…In the present study, we have employed chromium doping during crystal growth, as in Ref. [12]. One of the goals of our present study is searching the still unknown influence of the CdSe x S 1Àx matrix composition on the location of the chromium intracenter transitions in the IR-range.…”

Progress in Cr2+and Fe2+doped mid‐IR laser materials

“…In spite of these difficulties, TM:II-VI single crystals with good laser characteristics were reported by several groups. More details on TM doped II-VI crystal fabrication are available in the following publications: Chromium doped-ZnSe (PVT [17,18]), CdSe (PVT [19], gradient freezing [20]), CdS 1−x Se x (PVT [19,21]), CdTe (Bridgman [22]), Cd 1−x Mn x Te (Bridgman [22,23]); Iron dopedZnSe (PVT [17]), CdSe (Bridgman [24]), CdTe (Bridgman [24]), Cd 1−x Mn x Te (Bridgman [12]). …”

Bonding characters of M‐Cd4Te4 and M‐Cd3Te3 (M = Cr, Cu, Ag, Al, Cd, and Zn) clusters

“…In experiment, many Cr-CdX materials have been reported. Synchronously, their electronic, optical, and magnetic characters were investigated [9][10][11][12][13][14][15][16][17][18][19]. In 2007, Raman electron paramagnetic resonance of the transitions due to the spin flip of the 3d electrons of Cr þ in Zn 1-x Cr x Te and Cd 1-x Cr x Te is observed by Lu et al [20].…”