The growth of GaAs and InAs dots on etched mesas: The effect of substrate temperature on mesa profile and surface morphology on dot distribution

Fabrication of a self-aligned cross-wire quantum-dot chain light emitting diode by molecular beam epitaxial regrowth

“…Alternatively, QD chains can form on the top of ridge mesas. This is due to net migration from sidewalls to the mesa top, together with the relaxation of strain energy possible on convex-curved surfaces [16][17][18][19][20][21][22][23]. Such ridge-shaped substrates have the added advantage that they can significantly enhance the luminescence extraction efficiency compared to planar substrates [24].…”

“…These ridge mesas can be formed by pre-patterning the surface with large mesas which subsequently narrow during buffer layer overgrowth due to surface faceting and subsequent net adatom migration between neighbouring facets [16,22,23,21], or by selective area epitaxy where ridge-shaped mesas grow in windows in an amorphous oxide surface mask layer [19,17]. The latter method has been the most successful method so far in fabricating single chains of dots of uniform size once the mesa top surface is less than 50 nm wide in the InAs/InP material system [19] and in InAs/GaAs structures grown by chemical beam epitaxy [17]; however, it is less successfully applied to solid source InAs/GaAs MBE growth due to the high sticking coefficient of GaAs onto the mask material at conventional growth temperatures [25,26].…”