Optics of Quantum Dots and Wires
Quantum technology is the key to next-generation optoelectronics and laser semiconductors, and this cutting-edge book is an in-depth examination of how quantum dots and wires are fabricated and applied to optics.
TABLE OF CONTENTS Optics of Quantum Dots and Wires
6.2: SELF-ORDERING OF NONPLANAR SURFACES
6.2 SELF-ORDERING OF NONPLANAR SURFACES
In this section, we will summarize the characteristics of self-limiting surface profiles that develop during OMCVD on nonplanar substrates. An arbitrary surface profile initially develops faceting in certain crystallographic planes in order to minimize its surface energy. The particular set of planes that evolves depends on the orientation of the base substrate and the nonplanar features produced in the lithography step. The size of these facets evolves in a manner that is related to the local growth rate at each one of the facets. The establishment of a self-limiting nonplanar surface profile and its parameters arise from the interplay among growth rate anisotropy, capillarity, and entropy of mixing effects, all of which can be tuned by modifying the growth conditions and by selecting the layer compositions.
A quantitative model that describes the self-limiting growth of a nonplanar surface is first developed for a rather general case. The model is corroborated by the observed growth characteristics of self-limiting V-groove templates obtained by OMCVD on [011 1]-oriented channels made on (100) GaAs substrates. These nonplanar patterns are typically prepared using anisotropic wet chemical etching through masks made by photolithography or electron beam lithography.
6.2.1 Self-limiting Growth of V-grooves
For 2D growth on planar, isotropic substrates, the local growth rate is determined by the arrival rate of the source molecules or atoms at a given point on the surface. To produce a laterally structured surface, and eventually lateral heterostructures, it is desirable to laterally control the growth...
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