Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 57: Poster IIa

HL 57.13: Poster

Dienstag, 8. März 2005, 16:30–19:00, Poster TU E

Optical properties and ion-damage problems of nano-fabricated GaN structures using focused-ion-beam etching — •H. Lohmeyer, K. Sebald, J. Gutowski, R. Kröger, J. Dennemarck, and D. Hommel — Institute of Solid State Physics, University of Bremen, Germany

Focused-ion-beam (FIB) etching is a promising technique for the fabrication of structures on a submicron scale which are required for the realisation of novel optoelectronic devices. So far there are few reports on the application of the FIB process to GaN samples especially with respect to possible ion damage affecting the optical properties. We present results of spatially resolved photoluminescence (µ-PL) investigations on FIB-processed InGaN/GaN quantum well samples.

Structures with lateral dimensions of 20 µm down to 200 nm have been prepared using a FEI NOVA NanoLab 200 system. By scanning electron microscopy the conformity of the structures for various etching parameters was controlled.

The µ-PL analysis reveals a fatal surface damage on large scales already at intermediate ion currents when working on unprotected samples. We show that the use of appropriate beam currents and protection layers enables us to fabricate structures on a submicron scale without significant ion damage. The optical properties of these small mesa structures which allow PL experiments with sub-wavelength resolution are discussed in detail.