Showing papers by "Jong Hyun Ahn published in 2006"

Heterogeneous Three-Dimensional Electronics by Use of Printed Semiconductor Nanomaterials

Abstract: We developed a simple approach to combine broad classes of dissimilar materials into heterogeneously integrated electronic systems with two- or three-dimensional layouts. The process begins with the synthesis of different semiconductor nanomaterials, such as single-walled carbon nanotubes and single-crystal micro- and nanoscale wires and ribbons of gallium nitride, silicon, and gallium arsenide on separate substrates. Repeated application of an additive, transfer printing process that uses soft stamps with these substrates as donors, followed by device and interconnect formation, yields high-performance heterogeneously integrated electronics that incorporate any combination of semiconductor nanomaterials on rigid or flexible device substrates. This versatile methodology can produce a wide range of unusual electronic systems that would be impossible to achieve with other techniques.

High-speed mechanically flexible single-crystal silicon thin-film transistors on plastic substrates

Abstract: This letter describes the fabrication and properties of bendable single-crystal-silicon thin film transistors formed on plastic substrates. These devices use ultrathin single-crystal silicon ribbons for the semiconductor, with optimized device layouts and low-temperature gate dielectrics. The level of performance that can be achieved approaches that of traditional silicon transistors on rigid bulk wafers: effective mobilities>500cm/sup 2//V/spl middot/s, ON/OFF ratios >10/sup 5/, and response frequencies > 500 MHz at channel lengths of 2 /spl mu/m. This type of device might provide a promising route to flexible digital circuits for classes of applications whose performance requirements cannot be satisfied with organic semiconductors, amorphous silicon, or other related approaches.

Bendable GaN high electron mobility transistors on plastic substrates

Abstract: A procedure for fabricating flexible forms of high electron mobility transistors (HEMTs) supported on plastic substrates is described. The process uses a combination of conventional top-down, wafer scale fabrication protocols to define a printable form of ultrathin, device quality multilayer AlGaN∕GaN single crystalline microstructures—a so-called microstructured semiconductor ink—and soft-lithographic printing methods to effect their registered transfer to a plastic substrate. These procedures yield high performance, bendable HEMT arrays that are mechanically durable—ones with effective transconductances exceeding nearly all reported forms of printed thin-film transistors.