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Title: Superheating Suppresses Structural Disorder in Layered BiI3 Semiconductors Grown by the Bridgman Method

The susceptibility of layered structures to stacking faults is a problem in some of the more attractive semiconductor materials for ambient-temperature radiation detectors. In the work presented here, Bridgman-grown BiI3 layered single crystals are investigated to understand and eliminate this structural disorder, which reduces radiation detector performance. The use of superheating gradients has been shown to improve crystal quality in non-layered semiconductor crystals; thus the technique was here explored to improve the growth of BiI3. When investigating the homogeneity of non-superheated crystals, highly geometric void defects were found to populate the bulk of the crystals. Applying a superheating gradient to the melt prior to crystal growth improved structural quality and decreased defect density from the order of 4600 voids per cm3 to 300 voids per cm3. Corresponding moderate improvements to electronic properties also resulted from the superheat gradient method of crystal growth. Comparative measurements through infrared microscopy, etch-pit density, x-ray rocking curves, and sheet resistivity readings show that superheat gradients in BiI3 growth led to higher quality crystals.
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Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0022-0248; 830403000
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Crystal Growth; Journal Volume: 433
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
Country of Publication:
United States
Defects; Bridgman growth; Halides; Bismuth Compounds; Semiconducting Materials