Estrogen detection in water by silicon based light emitters

The immediate and accurate monitoring of chemical and biological substances is essential in environmental analysis for minimizing the health risk for citizens and their exposure to pollutants. Recently, considerable attention has been focused on endocrine-disrupting compounds (EDCs), such as estrogens, which constitute a wide group of environmental pollutants, especially in drinking water.
A new concept for measuring the concentration of such organic compounds by using Si-based, integrated light sources for fluorescence analysis is presented. In that concept the analyte, estrogen in this example, is labelled with a fluorescence marker and is immobilized at the passivated surface of the light emitter by receptor molecules.
The ion beam technology is one of the most essential steps of the light emitter fabrication. The integrated light emitters are based on a metal-oxide-semiconductor (MOS) structure. This oxide layer is implanted with Ge or rare earth ions (Gd and Tb) followed by annealing and SiON deposition. Depending on the implanted element there is a broad palette of MOS devices emitting light from the UV up to the red spectral region. The combination between Si-based integrated light emitter and this kind of biosensing opens a way to extremely small device dimensions and is of great interest for point-of-care measurements.

The current system was investigated Fourier-Transform infrared spectroscopy (FTIR), x-ray-photoelectron spectroscopy, photoluminescence (PL) and electroluminescence (EL) measurements.