Digital imaging technologies have enhanced archaeological research and profoundly expanded the scale of the discipline’s potentialities. As illustrators and archaeologists move away from using hand-drawn images (of hand-held, real-life objects) to depict artifacts and other archaeological information, certain capabilities of the traditional illustrative process are lost. One such loss is the ability to present a complete and informed representation of an artifact free of the distortions and visual limitations that single-perspective (i.e., digital or photographic) imagery produces. This is accomplished by the illustrator through the unification of multiple views of the artifact from various perspectives into a single two-dimensional image that communicates to the viewer important attributes of the artifact, free of distortion and remaining true to the measured, analytical conventions of the illustrative process. Liberation from the single-viewpoint perspective was one of the fundamental elements of the Cubist movement. Traditional archaeological illustrators utilize Cubist principles to communicate visually to the viewer a complete, accurate, and undistorted package of information about an artifact. The supplanting of hand-drawn illustrations by digital images in today’s archaeological publications threatens to revert the visual representation of data back to uninformed, surficial “snapshots” of incomplete objects.

A new process route for lateral growth of nearly defect free GaN structures via Pendeo-epitaxy is discussed. Lateral growth of GaN films suspended from {110} side walls of [0001] oriented GaN columns into and over adjacent etched wells has been achieved via MOVPE technique without the use of, or contact with, a supporting mask or substrate. Pendeo-epitaxy is proposed as the descriptive term for this growth technique. Selective growth was achieved using process parameters that promote lateral growth of the {110} planes of GaN and disallow nucleation of this phase on the exposed SiC substrate. Thus, the selectivity is provided by tailoring the shape of the underlying GaN layer itself consisting of a sequence of alternating trenches and columns, instead of selective growth through openings in SiO2 or SiNx mask, as in the conventional lateral epitaxial overgrowth (LEO).

Two modes of initiation of the pendeo-epitaxial GaN growth via MOVPE were observed: Mode A - promoting the lateral growth of the {110} side facets into the wells faster than the vertical growth of the (0001) top facets; and Mode B - enabling the top (0001) faces to grow initially faster followed by the pendeo-epitaxial growth over the wells from the newly formed {110} side facets. Four-to-five order decrease in the dislocation density was observed via transmission electron microscopy (TEM) in the pendeo-epitaxial GaN relative to that in the GaN columns. TEM observations revealed that in pendeo-epitaxial GaN films the dislocations do not propagate laterally from the GaN columns when the structure grows laterally from the sidewalls into and over the trenches. Scanning electron microscopy (SEM) studies revealed that the coalesced regions are either defect-free or sometimes exhibit voids. Above these voids the PEGaN layer is usually defect free.

A new process route for lateral growth of nearly defect free GaN structures via Pendeoepitaxy is discussed. Lateral growth of GaN films suspended from {1120} side walls of [0001] oriented GaN columns into and over adjacent etched wells has been achieved via MOVPE technique without the use of, or contact with, a supporting mask or substrate. Pendeo-epitaxy is proposed as the descriptive term for this growth technique. Selective growth was achieved using process parameters that promote lateral growth of the { 1120) planes of GaN and disallow nucleation of this phase on the exposed SiC substrate. Thus, the selectivity is provided by tailoring the shape of the underlying GaN layer itself consisting of a sequence of alternating trenches and columns, instead of selective growth through openings in SiO2 or SiNx mask, as in the conventional lateral epitaxial overgrowth (LEO).

Two modes of initiation of the pendeo-epitaxial GaN growth via MOVPE were observed: Mode A - promoting the lateral growth of the {1120} side facets into the wells faster than the vertical growth of the (0001) top facets; and Mode B - enabling the top (0001) faces to grow initially faster followed by the pendeo-epitaxial growth over the wells from the newly formed {1120} side facets. Four-to-five order decrease in the dislocation density was observed via transmission electron microscopy (TEM) in the pendeo-epitaxial GaN relative to that in the GaN columns. TEM observations revealed that in pendeo-epitaxial GaN films the dislocations do not propagate laterally from the GaN columns when the structure grows laterally from the sidewalls into and over the trenches. Scanning electron microscopy (SEM) studies revealed that the coalesced regions are either defect-free or sometimes exhibit voids. Above these voids the PEGaN layer is usually defect free.