Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster 1
HL 13.39: Poster
Montag, 26. März 2007, 15:00–17:30, Poster A
Investigation of Heterojunction Sharpness of III-V-Nanowhiskers by Analytical (S)TEM Measurements — •Daniela Sudfeld1, Jochen Kästner1, Günter Dumpich1, Ingo Regolin2, Werner Prost2, and Franz Josef Tegude2 — 1Department of Physics, Experimental Physics - AG Farle, University of Duisburg-Essen, Lotharstr. 1, 47048 Duisburg — 2Solid State Electronics Dept., University of Duisburg-Essen, Lotharstr. 55, ZHO, D-47048 Duisburg
High crystal quality single GaAs/InGaAs/GaAs and GaAs/GaP/GaAs nanowhiskers were grown by MOVPE on (111)B GaAs substrates using the VLS growth mode. Energy-dispersive X-ray spectroscopy (EDS) measurements were performed to investigate (1) the interface sharpness of group-III versus group-V transitions, and (2) lateral transitions attributed to a parasitic conventional layer growth forming a core-shell structure perpendicular to the growth direction. The results show that group-III transitions exhibit long tails attributed to a memory effect of the group-III species in the Au droplet, while lateral sharp core-shell GaAs/InGaAs/GaAs heterojunctions were found [1]. In contrast, the transition of the GaAs/GaP/GaAs whisker is much sharper due to a lacking memory effect of group-V species in the seed particle. These results provide important rules for an appropriate design of heterojunction nanowhisker devices. Acknowledgement: This work was supported by the DFG (SFB 445). Reference: [1] I. Regolin et al., Journal of Crystal Growth (2006), in press.