Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 108: Poster: Ultra-fast phenomena / Optical properties / Semiconductor laser / Devices and device concepts
HL 108.11: Poster
Thursday, April 3, 2014, 17:00–20:00, P1
Design and fabrication of acoustic devices in ZnO/SiO2 planar microcavities — •Jakov Buller1, Odilon D. D. Couto Jr.2, Edgar A. Cerda-Méndez1, Sander Rauwerdink1, Abbes Tahraoui1, and Paulo V. Santos1 — 1Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany — 2Universidade Estadual de Campinas, Campinas, Brazil
Optical resonances in semiconductor microcavities (MC) have been exploited to enhance the light emission from single emitters, while surface acoustic waves (SAWs) have been used to modulate the band gap of semiconductor nanostructures. In this work, we investigate the acousto-optical effects in planar ZnO/SiO2 MCs rf-sputtered on sapphire. The sample design is based on numerical calculations which show that: (i) the refractive index contrast of ZnO and SiO2 leads to high optical confinement; (ii) the piezoelectricity of ZnO enables the electric generations of SAWs for modulation of the MC resonance.
The fabricated two types of MCs consisting of a λ/2 active region spacer sandwiched by λ/4 ZnO/SiO2 distributed Bragg mirrors (DBRs). In the first one, the λ/2 spacer consists of an electron beam resist (HSQ). SEM measurements demonstrate successful resist planarisation, leading to homogeneous cavity spacers. In the second type, the upper DBR is mechanically glued on the lower one, thus forming air-gap MCs. Reflectivity measurements in MCs demonstrate quality (Q) factors of up to 2000, which are in reasonable agreement with transfer-matrix calculations. The process allows the insertion of light emitters into the MC active region and their manipulation by SAWs.