Dislocations cathodoluminescence

Cathodoluminescence microscopy and spectroscopy techniques are powerful tools for analyzing the spatial uniformity of stresses in mismatched heterostructures, such as GaAs/Si and GaAs/InP. The stresses in such systems are due to the difference in thermal expansion coefficients between the epitaxial layer and the substrate. The presence of stress in the epitaxial layer leads to the modification of the band structure, and thus affects its electronic properties it also can cause the migration of dislocations, which may lead to the degradation of optoelectronic devices based on such mismatched heterostructures. This application employs low-temperature (preferably liquid-helium) CL microscopy and spectroscopy in conjunction with the known behavior of the optical transitions in the presence of stress to analyze the spatial uniformity of stress in GaAs epitaxial layers. This analysis can reveal,... 

Gragert and Meyer (Fig. 6.2.1) and Boyarskaya (Fig. 6.2.2) by observation of surface deformations induced by indentation with a tungsten carbide ball and by scratch. The observations were carried out using secondary electron beam and in cathodoluminescence. They demonstrated on MgO and LiF crystals the occurrence of cracks around the impression of the ball similar to those induced by a Vickers indenter, and also the occurrence of a concentration of screw and edge dislocations in the area of the cracks. 

Light (cathodoluminescence) UV, visible, IR Interband transitions between higher energy levels Imaging dislocations In semiconductors... 

K. Maeda, K. Nakagawa, S. Takeuchi, K. Sakamoto, Cathodoluminescence studies of dislocation motion in Ob—VIb compounds deformed in SEM, J. Mater. Sci. 16 (1981) 927—934. S. Sadakuni, J. Miurata, K. Yagi, Y. Sano, K. Arima, A.N. Hattori, T. Okamoto, K. Yamauchi, Influence of the UV tight intensity on the photoelectrochemical planarization technique for gallium nitride. Mater. Sci. Forum 645 (2010) 795—798. 

Figure 25. One-to-one correspondence between (a) dislocation etch-pit distribution, (b) cathodoluminescence images and (c) electron-beam-induced conductivity images of the same region of a GaP layer (104).

---