SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

1.3. LATTICE MISMATCHED STRUCTURES 19

Row of atoms

have only 3

nearest

neighbor bonds

Figure 1.14: A schematic showing the presence of a dislocation. This line defect is produced by
adding an extra half plane of atoms.

Figure 1.15: TEM image of an InP/InAs double-barrier resonant tunneling device (DBRT) con-
sisting of 5 nm InP barriers surrounding a 15 nm InAs quantum dot. The InP is coherently
strained, with no dislocations created at the interfaces. Image courtesy of M. Bjork, Lund Uni-
versity.