Porous silicon chemical sensors and biosensors: A review

The use of porous silicon (PSi) as a sensor for detection of various analytes is reviewed. The optical or electrical properties of PSi are key sensing parameters that have been used in many chemical and biological sensing applications. PSi is a promising candidate due to ease of fabrication, large surface area, various accessible pore sizes and morphologies, controllable surface modification and its compatibility with conventional silicon processing technology. The adsorption of chemical or biological molecules into the pores modifies the electrical and/or optical properties, allowing convenient and sensitive measurement approach. In this review, we provide a critical assessment of the development of PSi as a promising material for chemical and biosensing applications. Formation procedures of PSi with various pore sizes and morphologies are firstly given. Surface properties and structural characteristics of the material are briefly described. The recent progress on utilization of such porous structures in chemical and biosensing applications is then addressed in the context of surface chemistry effects and nanostructures, measuring approaches, operating concepts and device sensitivity and stability. Finally, concluding remarks with existing challenges that hinder the material for commercial use are highlighted. (C) 2014 Elsevier B.V. All rights reserved.