Amorphous and nanocrystalline p-i-n Si and Si,Ge photodetectors for structurally integrated O-2 sensors

TitleAmorphous and nanocrystalline p-i-n Si and Si,Ge photodetectors for structurally integrated O-2 sensors
Publication TypeJournal Article
Year of Publication2008
AuthorsGhosh D, Shinar R, Dalal V, Zhou Z, Shinar J
Journal TitleJournal of Non-Crystalline Solids
Date PublishedMay
Type of ArticleProceedings Paper
ISBN Number0022-3093
Accession NumberISI:000256500400118
KeywordsDISSOLVED-OXYGEN, NANOCRYSTALLINE, plasma deposition, sensors, silicon

Recent efforts to develop compact, field-deployable photoluminescence (PL)-based chemical and biological sensors have focused on structurally integrating an array of organic light emitting device (OLED) pixels, which serve as the excitation source, with a sensing film, and a thin-film photodetector (PD). To that end, VHF and ECR were used for fabricating and comparing amorphous and nanocrystalline p-i-n Si- and Si,Ge-based PDs for monitoring O-2, which is preferably determined by monitoring the PL decay time, rather than the PL intensity, of the sensing film. This approach eliminates the need for frequent sensor calibration and, as pulsed OLED excitation is employed in this mode, the need for optical filters, which lead to bulkier sensors. Therefore, the development of the PDs also focused on increasing their speed, and understanding the factors affecting it, such as the device structure and boron diffusion during growth from the p+ to the i layer in p-i-n PDs. Incorporating a SiC buffer layer at the p+/i interface and a superstrate structure, where the p+ layer was grown last, increased the speed. The effects of Ge, p+ layer thickness, nanocrystallinity, defect states, and the illumination wavelength on the speed are also discussed. (C) 2007 Elsevier B.V. All rights reserved.

Alternate JournalJ. Non-Cryst. Solids