Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 84: Poster: Electronic structure theory / Carbon (other than graphene) / Si, Ge, and SiC / III-V semiconductors (other than nitrides)
HL 84.21: Poster
Mittwoch, 2. April 2014, 17:00–20:00, P1
Self-assembled growth of InxGa1-xAs quantum dots on GaP by gas-source molecular-beam epitaxy — •Shabnam Dadgostar1, Fariba Hatami1, W. Ted Masselink1, Jan Schmidtbauer2, and Torsten Boeck2 — 1Departmant of physics, Humboldt university of Berlin. Newtonstr. 15, 12489 Berlin. Germany. — 2Leibniz- Institute für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany
The InGaAs/GaP heterosystem is expected to be type I, suggesting its use for light emission. We have used gas-source molecular-beam epitaxy to grow InxGa1-xAs (x= 0.3, 0.5) quantum dots on GaP (100) substrates; the lattice mismatch is 6.0 and 7.4 %, x=0.3 and x=0.5. For a coverage of 2 monolayers of In0.3Ga0.7As deposited at 0.4 ML/s, however, AFM indicates the formation of high density of In0.3Ga0.7As quantum dots. Their density is 1.2 e11 cm-2, with average diameter and height of 12.5 nm and 2.5 nm, respectively. For In0.5Ga0.5As deposited under the same conditions, however, AFM measurements show evolution of large islands with diameter of 95 nm and height of 20 nm. The critical thickness for transition from two-dimensional to three-dimensional growth was determined by AFM results and it was found less than 1.5 and 1.3 monolayers for In0.3Ga0.7As and In0.5Ga0.5As respectively.