Misfit Dislocation: Lattice Mismatch

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Misfit Dislocation: Lattice Mismatch versus Misfit Dislocation Separation

Figure 2117 shows an example of cathodoluminescence (CL) images. This image was taken from a ZnSe/GaAs heterostructure. The dark-line defects (DLDs) formed primarily along (100) directions ([100] and [010]) in the area (labeled A) photodegraded by an argon laser. Some DLDs marked by arrowheads are misoriented by 5 to 25 degrees from the <100> directions. "M" in the figure marks a misfit dislocation.

an example of cathodoluminescence (CL) images

Figure 2117. Cathodoluminescence (CL) image taken from a ZnSe/GaAs heterostructure. Adapted from [1]

Table 2117 shows examples of the lattice mismatches between the substrates and epitaxial layers, and the critical layer thickness and the resulting misfit dislocation separation corresponding to complete misfit relaxation for the basal plane interfaces.

Table 2117. Examples of lattice mismatches between substrate A and epitaxial layer B, lattice parameter on the basal plane,

and critical layer thickness and resulting misfit dislocation separation for a fully relaxed interface.

A	B	a (Å)	Mismatch (%)	Critical thickness (Å)	Dislocation separation (Å)
GaN	GaN	3.186
GaN	In_0.1Ga_0.9N	3.222	1.07	21.4	286
GaN	In_0.2Ga_0.8N	3.258	2.14	10.7	145
GaN	In_0.4Ga_0.6N	3.329	4.28	5.36	74
GaN	In_0.6Ga_0.4N	3.401	6.42	3.57	50
GaN	In_0.8Ga_0.2N	3.473	8.56	2.68	39
GaN	InN	3.545	10.7	2.14	27
GaN	Sapphire		14.8		17.2
GaN	SiC		3.3		80.9
6H-SiC	Sapphire		11.5		21.9
6H-SiC	GaN		-3.3		80.9
α-A1₂0₃	SiC		-11.5		21.9
α-A1₂0₃	GaN		-14.8		17.2
InN	Sapphire		25.4		10.6
InN	SiC		14.0		20.4
InN	GaN		10.6		27.3
AlN	Sapphire		12.5		20.3
AlN	SiC		1.0		276.7
AlN	GaN		-2.4		114.4

[1] L. Salamanca-Riba and L.H. Kuo, Observation of [100] and [010] Dark Line Defects in Optically Degraded ZnSSe-Based LEDs by Transmission Electron Microscopy, Journal of Electronic Materials, 25 (2) (1996) 239.

Practical Electron Microscopy and Database

An Online Book, Second Edition by Dr. Yougui Liao (2006)

Misfit Dislocation: Lattice Mismatch versus Misfit Dislocation Separation