Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 44: Quantum dots and wires: preparation and characterization II
HL 44.6: Vortrag
Donnerstag, 28. Februar 2008, 18:00–18:15, EW 201
Influence of growth time and NH3 stabilisation flow on InN quantum dot formation by MOVPE — •S. Ploch1, C. Meissner1,2, M. Pristovsek1, and M. Kneissl1 — 1Institut für Festkörperphysik, TU Berlin, Hardenbergstr. 36, EW6-1, 10623 Berlin — 2ISAS - Institute for Analytical Sciences, Albert-Einstein-Str. 9, 12489 Berlin
Despite their unique electronic and optical properties very little attention has so far been devoted to the growth of InN quantum dots (QDs). In the present study we have investigated the metalorganic vapour phase epitaxy (MOVPE) of InN QDs on GaN/sapphire by in-situ spectroscopic ellipsometry. Three-dimensional nanostructures with a mean hight of 1.7 nm (corresponding to 6 monolayers of InN), a mean diameter of 16.5 nm and a density of 2·1011 cm−2 have been realized. In this case the InN QDs were grown for 60 s at a total reactor pressure of 100 mbar and a V/III ratio of 15,000. By decreasing the V/III ratio from 20,000 to the relatively low value of 5,000 we observed an increase of the total growth rate, which can be explained by reduced layer desorption due to the reaction of InN with atomic hydrogen from the ammonia pyrolysis. It should be noted that we were able to obtain high crystalline quality InN QDs even at low V/III ratios around 5,000 using an ammonia stabilisation flow. These growth conditions and times between 5 s and 60 s are very similar to growth of InAs QDs.