One factor limiting the scaling and reproducibility of device elements in computer processors is the random distribution of dopants in semiconductor nanostructures. To overcome this obstacle for faster computing, new ways to position and address individual dopants are needed. Proposals for next-generation computing based on quantum variables such as electron spin also require the ability to address and control interactions between individual atoms.

Ferroelectric materials are characterized by a spontaneous polarization that can be switched by external electric field. This property is important for various technological applications such ferroelectric random access memories. However, when ferroelectric film thickness is reduced down to a nanoscale the ferroelectric polarization may become unstable due to strong depolarization fields and interface effects.

High conductivity and efficient charge injection into organic layers could lead to the design of more efficient organic solar cells and molecular electronics, especially light emitting diodes. Most organic materials are however insulators and only few exhibit high conducting properties. Nebraska MRSEC researchers in collaboration with their colleagues at University of Puerto Rico have discovered that zwitterion molecules of the p-benzoquinonemonoimine type are different from being a standard insulator.

Photovoltaics is a method of converting solar radiation into electricity.  Some semiconducting materials exhibit a property known as the photoelectric effect that causes them to absorb light and release electrons. In addition to the semiconductors, ferroelectric materials have been employed to create ferroelectric-photovoltaic devices. In these devices, a ferroelectric thin film is used as a light absorbing layer and the electric field created by ferroelectric polarization is the driving force for the photocurrent.

To change the magnetization of a ferromagnet usually requires a magnetic field.  So, for example, if we put a compass needle into the high field of an MRI machine, we can no longer trust it to swivel to the North.  Similarly, the magnetic stripes on credit cards and key cards can be destroyed in high magnetic fields.  Electric fields don’t have the same effect on magnetic materials, which is just as well for everyday applications.

The detection of noxious gases or bio-agents is important for various environmental and security needs. High sensitivity, sufficient selectivity and molecular recognition are key characteristics for such sensing. Nebraska MRSEC researchers have developed a scheme for molecular sensing using magnetic tracer particles and a microcantilever torsional magnetometer. An example of using this system with a detection process is illustrated in the Figure below.