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HL: Halbleiterphysik

HL 2: III-V Halbleiter

HL 2.1: Vortrag

Montag, 24. März 2003, 10:30–10:45, BEY/118

Doping, Structure and Thermal Stability of nano-InP — •X.M. Li, Z. Guan, Th. Agne, H. Wolf und Th. Wichert — Technische Physik, Universität des Saarlandes, D-66123 Saarbrücken

Nanocrystalline InP with a particle size of 2-4 nm was synthesized via the reaction of dry InCl₃ with P(Si(CH₃)₃)₃ in trioctylphosphine (TOP) at 260^∘C. The InP nanocrystallites were doped with ¹¹¹In/¹¹¹Cd by mixing ¹¹¹InCl₃ with stable InCl₃. The samples were investigated using perturbed γγ-angular correlation spectroscopy (PAC), XRD and TEM. After preparation, more than 50% of the ¹¹¹In probe atoms have been found in the samples. The PAC data, however, do not show a cubic symmetry about the probe atoms, although the XRD data show that the as-prepared samples possess the typical zinc blende structure of InP. TEM and XRD analyses show that the particle size increases to only 5 nm at 500^∘C. At the same time, the PAC data show only a small fraction below 15% of the probe atoms to be on lattice sites with undisturbed cubic symmetry. The particle size increases to about 33 nm after annealing at 600^∘C and about 50% of the probe atoms are located on lattice sites with cubic symmetry as shown by PAC. The observed distortion of the local cubic symmetry of the nano-InP particles is obviously correlated with the particle size, which is also supported by theoretical calculations of Sudip Roy and Michael Springborg [1].

[1] Sudip Roy and Michael Springborg, accepted by J. Phys. Chem. B.

Supported by the DFG within the SFB277.