Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 34: Poster I: III-V Semiconductors

HL 34.5: Poster

Tuesday, March 23, 2010, 18:30–20:30, Poster D2

Low energy focused ion beam implantation on GaAs substrate for the preparation of site selected self-assembled InAs quantum dots — •Yu-Ying Hu and Andreas D. Wieck — Ruhr-Universität Bochum, D-44780 Bochum, Germany

Focused ion beam (FIB) technology has received attention for its utilization in fabricating nanostructures. The purpose of this study is to gain low energy ions by applying a high voltage on the target, e.g. in a retarding mode: the high potential will decelerate the 30 keV ions, generating a very low landing energy ion beam of the order of a few tens to a few hundreds of eV for deposition or implantation which yields implantation depths of about 1 nm according to SRIM simulations. In this manner, Indium atoms are placed in the uppermost monolayers which should enhance the self organization of InAs QDs inside the implanted region of a few µm size, resulting in local growth instead of random distribution which is the conventional growing characteristic of self-assembled QDs. For this experiment, an Indium liquid metal ion source is produced. Using an in situ focus ion beam connected with a molecular beam epitaxy (MBE) system allows then the growth of the QDs including an subsequent MBE-overgrowth without breaking the ultra high vacuum. The decelerating voltage to be employed on the GaAs target is at maximum 30 kV while the beam current will be scaled in the range of a few pA. IMPRS-SurMat is greatly acknowledged for providing the scholarship and T-courses.