(Electronics and Photonics Division Award Address) Let There be Light... – Research at the Intersection of Electronics and Photonics
Authors: Steckl Andrew 
Published: May 2020

Electronics and photonics have a long and successful history of combining to provide many devices and products that are at the heart of the modern technological world, ranging form solar cells to lasers to digital displays. In this presentation I will first give a brief historical overview of the interplay and interdependence of electronics and photonics. The properties and effects that are commonly exploited in opto/electronics fall primarily in two areas: (a) the effect of incident light (or more generally radiation) due to optical absorption/transmission/reflection and the conversion of photons to electrical charge that can be collected; (b) the injection of electrons & holes leading to the emission of photons. Then I will review selected examples from my research in optoelectronic materials and devices in more or less chronological order over the past 40+ years. An early example [1] in the light-to-charge was integration of infrared detectors using narrow bandgap semiconductors (such as InSb and HgCdTe) with silicon charge coupled devices that performed data storage and image processing functions on arrays of pixels. A major research topic in my group in the charge-to-light category has for many years been electroluminescence [2] from wide bandgap semiconductors (primarily GaN and AlN) doped with rare earth elements (Er, Eu, Tm, etc.). Narrow linewidth emission can occur at wavelengths from near UV to visible to IR, depending on the electronic transitions of the selected RE element and the bandgap of the host material. In the past 10 years, my materials interest switched from inorganic to organic semiconductors and biomaterials, but with a continuing strong opto/electronic component. Currently, a major research focus is in developing simple, low cost and intuitive diagnostic devices for point-of-care use. These devices analyze the composition of biofluids (e.g. blood, sweat, saliva, etc.) to provide a 1st order indication of specific aspects the individual’s health status, such as blood coagulation, stress, etc. The use of light in PoC and other diagnostic devices is widespread. Most common and simplest approach is colorimetric detection in ambient light, where a change of color in a region of the device indicates the presence of a specific biomolecule associated with a given medical condition. Somewhat more complex diagnostic devices use fluorescence of molecules attached to biomarkers to indicate their presence. In our own research, biofluid samples are typically transported by capillary flow to a location where their key properties are measured by a combination of optical emission [3], transmission and absorption [4]. The presentation will conclude with a look forward to other applications where photonics and electronics could join forces.
[1] A.J. Steckl, et al., “Application of Charge Coupled Devices to Infrared Detection and Imaging,” Proc. of IEEE, 63(1), 67, Jan 1975 ( doi.org/10.1109/PROC.1975.9708 ).
[2] (a) A.J. Steckl and J.M. Zavada, “Optoelectronic Properties and Applications of Rare-Earth-Doped GaN”, Mat. Res. Soc. Bulletin, 24(9), 33, Sep 1999 doi.org/10.1557/S0883769400053045; (b) A. J. Steckl, et al., Invited Paper, “Rare-earth-doped GaN: Growth, Properties and Fabrication of Electroluminescent Devices”, IEEE J. Selected Topics in Quantum Electronics, 8 (4), 749 Jul 2002 doi.org/10.1109/JSTQE.2002.801690

[3] V. Venkatraman and A. J. Steckl, “Quantitative Detection in Lateral Flow Immunoassay Using Integrated Organic Optoelectronics”, IEEE Sensors, 17 (24), 8343, Dec 2017 (doi.org/10.1109/JSEN.2017.2764178 ).
[4] P. Ray and A. J. Steckl, “Label-Free Optical Detection of Multiple Stress Biomarkers in Sweat, Plasma, Urine and Saliva”, ACS Sensors
4, 1346, 2019. (doi.org/10.1021/acssensors.9b00301).

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