High performance nanowire macroelectronics

Macroelectronic circuitry implemented on non-crystalline substrates such as glass and plastic holds the promise of making computing devices ubiquitous due to their light weight, flexibility, and low cost. However, the temperature restrictions imposed by these substrates restrict the use of high carrier mobility materials, such as polycrystalline silicon, generally limiting these devices to the modest computational capabilities of amorphous silicon and organic semiconductor thin film transistors (TFTs). The introduction of an ambient temperature route for producing and integrating high-mobility semiconductors on flexible substrates could enable the development of novel electronic and photonic devices with the potential to impact a broad spectrum of applications.; Semiconductor nanowires (NWs) can function both as active electrical components and as efficient conduits for the transport of charge carriers, and hence represent unique building blocks for electronic and photonic devices. This thesis presents recent studies demonstrating that films of single-crystal nanowires can be assembled onto inexpensive glass and flexible plastic substrates under ambient conditions to create high performance, multi-component devices such as field-effect transistors (FETs), light-emitting diodes (LEDs), and fully integrated ring oscillators.; The key to our approach is the separation of the high temperature synthesis of single-crystal nanowires from room temperature solution-based assembly, thus enabling the fabrication of single-crystal devices with diverse functionalities on virtually any substrate. Silicon nanowire field-effect transistors on plastic substrates display mobilities rivaling those of single-crystal silicon and exceeding those of state-of-the-art amorphous silicon and organic transistors currently used for flexible electronics on plastic substrates. Furthermore, we show that these systems can be integrated into logical inverters with gain under both DC and AC conditions up to frequencies approaching the microwave regime. On-chip integration of multiple inverters on glass and plastic substrates allows for the generation of ring oscillators with frequencies above 30 MHz, the highest observed frequency for circuits based on nanoscale materials. The generality of this bottom-up assembly approach suggests the integration of diverse nanoscale building blocks on a variety of substrates, potentially enabling far-reaching advances in lightweight display, mobile computing, and information storage applications.