Integrated semiconductor fluorescent detection system for biochip and biomedical applications

摘要

As biological analysis systems scale to smaller dimensions, the realization of small and portable biosensors becomes increasingly important. The innovation of integrated fluorescence sensors is now possible due to the development of optoelectronics over the past decade. We present the monolithic integration of vertical cavity surface emitting lasers (VCSELs), PIN photo-detectors and optical emission filters to be used as a fluorescence sensor. The integration will drastically reduce cost and size of fluorescence detection systems. Also, parallel sensing architectures of more than one hundred channels will be possible. The sensor will be utilized for near-infrared fluorescence detection. This spectral range is compatible with standard AlGaAs optoelectronic technology and will also reduce background fluorescence from complex bio-fluids such as blood. PIN heterostructure photodetectors have been fabricated and tested. Photodetector experiments show extremely low dark current of less than 500fA/mm, quantum efficiency greater than 85 percent and linear detector response. Optical simulations have been preformed to evaluate the performance of a proximity sensing architecture. These simulations predict a detection sensitivity lower than 10000 fluorescent molecules in a detection area of 10~4 μm~2.