Quantum dots light emitting devices on MEMS: microcontact printing, near-field imaging, and early cancer detection

Abstract

Controlled patterning of light emitting devices on semiconductors and micro-electro-mechanical systems (MEMS) enables a vast variety of applications such as structured illumination, large-area flexible displays, integrated optoelectronic systems and micro-total analysis systems for real-time biomedical screening. We have demonstrated a series of techniques of creating quantum dot-based (QD) patterned inorganic light emitting devices at room temperature on silicon (Si) substrate. The innovative technology was translated to create localized QD-based light sources for two applications: (1) Three-dimensional scanning probe tip structures for near field imaging. Combined topographic and optical images were acquired using this new class of "self-illuminating" probe in commercial NSOM. The emission wavelength can be tuned through quantum-size effect of QDs. (2) Multispectral excitation sources integrated with microfluidic channels for tumor cell analyses. We were able to detect the variation of sub-cellular features, such as the nucleus-to-cytoplasm ratio, to quantify the absorption at different wavelength upon the near-field illumination of individual tumor cells towards the determination of cancer developmental stage.Keywords： quantum dots, LED, microcontact printing, micro-electro-mechanical systems (MEMS), silicon scanning probe, multispectral imaging, near field scanning optical microscopy, cancer detection.

Recent Developments in Applications of Quantum-Dot Based Light-Emitting Diodes

“…There are a lot of studies that demonstrated a number of procedures of creating QD-LEDs through microcontact printing of QDs on a micromachined silicon probe and resulting in this way a novel generation of highly integrated nano-scale optical fluorescent microscopy [76,78]. The use of this innovative technology permits to detect the variation of sub-cellular characteristics and to measure the absorption at various wavelengths upon the near-field lighting of individual tumor cells with the aim of the identification of the cancer developmental phase [76].…”

“…The use of this innovative technology permits to detect the variation of sub-cellular characteristics and to measure the absorption at various wavelengths upon the near-field lighting of individual tumor cells with the aim of the identification of the cancer developmental phase [76].…”

“…QD-LEDs manufactured on silicon have the potential to be used in nanophotonics, optical micro/nanoelectromechanical systems (MEMS/NEMS), and micrototal analysis systems for real-time biomedical screening [21,76]. QD-LEDs are of considerable interest for new optoelectronic applications such as that which comprise near-field microscopy beyond the diffraction limit, MEMS-based medical endoscopes for sub-cellular imaging, and compact light-on-chip biosensor and biochips [21].…”