Regensburg 2025 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 39: Poster III

HL 39.23: Poster

Wednesday, March 19, 2025, 15:00–18:00, P3

Development of a VCSEL-chip in the red spectral range with integrated photodiode for chlorophyll fluorescence analysis — •Raphael Buffler, Michael Zimmer, Michael Jetter, and Peter Michler — Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum-Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart

Chlorophyll fluorescence analysis provides information on photosynthetic activity of plants and thus also on their health. Changes in the environmental conditions can be monitored on large scale and, water and nutrients can be added as needed. In order to induce the fluorescence of chlorophyll in the range from 660 nm to 750nm , optical excitation at 650 nm can be used. In this work, a semiconductor chip will be developed that contains both, the light source for excitation and the photodiode for fluorescence detection. The chip is based on the AlGaAs & AlGaInP material systems, which can realise the band gaps for the required wavelengths. The light source is designed as a vertical-cavity surface-emitting laser (VCSEL), which allows for the vertical emission of the excitation light and the vertical irradiation of the photodiode. A stacked arrangement is used, where the VCSEL is grown by metal-organic vapor-phase epitaxy (MOVPE) on top of the photodiode structure on a GaAs wafer. First electro-optical characteristics of the VCSEL and the photodiode such as P-U-I curves, emission wavelength and photodiode responsivity are presented.

Keywords: VCSEL; Photodiode; Chlorophyllfluorescence; AlGaAs; GaInP