Twins in CdMnTe single crystals grown by Bridgman method

Abstract

Cd 1-x Mn x Te (x=0.2, CdMnTe) crystal was grown by the vertical Bridgman method, which exhibits a pure zincblende structure in the whole ingot. The major defect, twins, which is fatal to CdMnTe crystal, was analyzed with scanning electron microscopy (SEM), X-ray energy disperse spectroscopy (XEDS) and optic microscopy on the chemical etching surface. The twins observed in the as-grown ingot are mainly lamellar ones, which lie on the {111} faces from the first-to-freeze region of the ingot and run parallel to the growth axis of the ingot. Coherent twins with {115} t -{111} h orientations when indexed with respect to both the twin and host orientations, are often found to be terminated by {110} t -{114} h lateral twins. Te inclusions with about 20 µm in width are observed to preferentially decorate the lamellar twin boundaries. The origin of the twins, relating to the growth twin and the phase transformation twin, is also discussed in this paper.

Vertical Bridgman growth and characterization of Cd0.95-xMnxZn0.05Te (x=0.20, 0.30) single-crystal ingots

“…Both the crystals are single-grain with large number of twins. Our date is in agreement with the analyses the morphology and crystallography of twins in Cd 1-x Mn x Te (x=0.2) crystal in [8,9] and heavily twinned crystal with x = 0.20 and 0.35 in [3]. Thus, 0.05 mol.…”

Vertical Bridgman growth and characterization of Cd_0.95-xMn_xZn_0.05Te (x=0.20, 0.30) single-crystal ingots

“…Both the crystals are single grain with a large number of twins. Our work is in agreement with the analyses of the morphology and crystallography of twins in Cd1-xMnxTe (x=0.2) crystals in [8,9] and heavily twinned crystals with x = 0.20 and 0.35 in [3]. Thus, 0.05 mol.…”

Solution growth of In-doped CdMnTe crystals by the vertical Bridgman method with the ACRT technique

“…Te particles are often associated with radial strain fields and dislocation loop punching, which can affect charge transportation properties of CdMnTe crystals [3]. Two methods can be adopted to reduce the twins in CdMnTe crystal, one is using the highquality CdMnTe seed growth method, since a large number of transformation twins is a consequence of isolated defect sites at which the solid-state transition nucleates [9], and another is using the Te excess solution technique to grow CdMnTe crystal below the phase-transformation temperature to avoid the phasetransformation twins [10].…”

“…The use of the vertical Bridgman method is well established and widely practiced to grow CdMnTe crystal. However, the high tendency of twin-formation in CdMnTe crystals is a severe problem for detector application due to its high ionicity of chemical bond and low stacking fault energy [7][8][9]. In addition, solid state phase transformation from wurtzite to zinc blende structure during the melt cooling process can introduce the phase transformation twins [8][9][10].…”