In this paper, we demonstrate the integration of high-performance single crystalline inorganic µ-light emitting diodes (LEDs) onto unconventional substrates such as plastic and glass via self-assembly. AlGaAs-based free-standing red µ-LEDs were batch fabricated and released from their substrates for use in self-assembly. The templates for assembly were fabricated on substrates such as flexible plastics and glass. The self-assembly method is capable of positioning the micro-components onto the template in proper receptor sites with a high yield, and forming electrical connections between components and the template with 62% yield. The µ-LEDs remain functional even after significant bending and deformation of the plastic substrates. The self-assembly method offers a way to incorporate optoelectronics onto objects that are incompatible with conventional semiconductor manufacturing processes.

A protein patterned surface using micro-contact printing methods has been investigated by scanning force microscopy. Electrostatic force microscopy (EFM) was utilized for imaging the topography and detecting the electrical properties such as the local bound charge distribution of the patterned proteins. It was found that the patterned IgG proteins are arranged down to 1 µm, and the 90° rotation of patterned anti-IgG proteins was successfully undertaken. Through the estimation of the effective areas, it was possible to determine the local bound charges of patterned proteins which have opposite electrostatic force behaviors. Moreover, we studied the binding probability between IgG and anti-IgG in a 1 µm(2) MIMIC system by topographic and electrostatic signals for applicable label-free detections. We showed that the patterned proteins can be used for immunoassay of proteins on the functional substrate, and that they can also be used for bioelectronics device application, indicating distinct advantages with regard to accuracy and a label-free detection.