Here, we report on the formation of homogeneous nanostructures and the thermal properties of quaternary system with AgPb _m SbTe _m+2 ( m = 18) that were synthesized via nanostructure crystallization engineering.

Frank-type stacking faults in 4H–SiC epitaxial layers were investigated using room-temperature photoluminescence mapping and high-angle annular dark-field high-resolution scanning transmission electron microscopy. Remarkably, the intrinsic Frank-type stacking fault (5,2) and intrinsic multilayer Frank-type stacking fault (4,2), which have been reported to have elongated triangular shapes to date, were found to have broader triangular shape, which was typical shape of Shockley-type stacking faults. The shaping of stacking faults could be explained based on the directions of the partial dislocations bounding the stacking faults. Formation models for the intrinsic (5,2) and (4,2) stacking faults were proposed. In addition, we observed Frank-type stacking faults (3,2,2,3) and (3,3) and Shockley-type stacking faults (3,3,3,2,3,2) and (3,2,3,3,3,2), which were not reported before. All of these stacking faults were composed with the stacking numbers 2 and 3 in the Zhdanov notation and showed very close characteristic photoluminescence emission wavelengths of 427–428 nm. Formation models for the stacking faults of (3,2,2,3), (3,3), (3,3,3,2,3,2), and (3,2,3,3,3,2) were proposed, also. Based on the proposed formation models of (4,2) and (3,3) stacking faults, formation models for the Frank-type stacking faults (4,1) and (3,2) were discussed. Finally, we pointed out that the (4,1) Frank-type stacking fault should be the intrinsic not the extrinsic fault, and the (3,2) Frank-type stacking fault is the extrinsic fault.

Five Σ-shaped dislocation arrays in 100-mm-diameter, 12-μm-thick 4H-SiC epitaxial wafers were observed using photoluminescence mapping. The structure of the Σ-shaped dislocation arrays was characterized using nondestructive analytical techniques of photoluminescence mapping, microphotoluminescence spectroscopy, and x-ray topography. Each Σ-shaped dislocation array consists of two basal plane dislocations (BPDs) at the interfacial dislocation terminal points and two half-loop arrays. The interfacial dislocation pairs nucleate from BPDs in the substrate. Three independent stresses lead to interfacial dislocations: thermal stress (τ_T), stress induced by misfit strain (τ_M), and interaction force (τ_I). The main cause of interfacial dislocation formation is attributed to the development of τ_T within the wafer due to temperature nonuniformity. τ_M and τ_I also contribute to the formation of interfacial dislocations. Larger stresses increase the BPD glide velocity in the interfacial dislocations, thereby producing longer Σ-shaped dislocation arrays.