TEM studies of structural defects in HgTe/HgCdTe quantum wells

Optical Studies and Transmission Electron Microscopy of HgCdTe Quantum Well Heterostructures for Very Long Wavelength Lasers

“…However, five QWs can be seen clearly, with the QW width being not less than 7.8 nm, the value provided by the in situ ellipsometry. High-resolution images of “dark areas” from the overview micrographs ( Figure 1 b) revealed defects similar to the ones studied in a recent work [ 38 ].Based upon the lateral average of contrast, we obtain the average width for QWs d = 8–12 nm. Notably, the QW width determined from TEM images in a recent work was also 2 nm larger than that extracted from the ellipsometry data [ 20 ].…”

Interface Studies in HgTe/HgCdTe Quantum Wells

“…Both images provide evidences of HgTe layers (QWs) with reasonably clear interfaces. A study of the defects visible in the layers allowed for tentatively identifying them as stacking faults, dislocations, dislocation loops, and lattice deformations …”

“…A study of the defects visible in the layers allowed for tentatively identifying them as stacking faults, dislocations, dislocation loops, and lattice deformations. [13] Figure 3 shows STEM/HAADF images of the studied samples. The images have a magnification similar to that used in Figure 2.…”