Rachel S. Goldman

Professor

rsgold@umich.edu

2094 H.H. Dow Building

T: (734) 647-6821

Bio

Projects

Publications

Research Facilities

Group


Current Projects

Fundamental Phenomena in Semiconductors: Diffusion and Segregation
Sponsor: American Chemical Society-Petroleum Research Fund 34012-AC5, Air Force Office of Scientific Research F49620-00-0328

Direct measurements of diffusion and segregation lengths are generally limited by the inherent averaging that occurs in conventional characterization techniques. We are investigating the atomic-scale dynamics of these processes using a combination of annealing and cross-sectional scanning tunneling microscopy (XSTM)....

Fundamental Phenomena in Semiconductors: Alloy Formation
Sponsor: National Renewable Energy Laboratory ACQ-1-31619, Air Force of Scientific Research F49620-00-0328, Office of Naval Research N000-021-0899

We are interested in the mechanisms of solute atom incorporation and alloy decomposition in dilute and concentrated semiconductor alloys, respectively. For example, we are exploring the effects of surface reconstruction during thin film growth on the incorporation of solute atoms...

Fundamental Phenomena in Semiconductors: Strain Relaxation
Sponsor: National Science Foundation DMR-9773707, DMR-0210714; National Renewable Energy Laboratory ACQ-1-31619

During heteroepitaxial growth of films and heterostructures, misfit strain may be relaxed elastically and/or plastically. Although the mechanisms of these strain relaxation processes have been studied for decades, the interplay between elastic and plastic relaxation, as well as the effects...

Structure-Property Correlations: Effects of Dislocations on Electron Mobility
Sponsor: National Science Foundation DMR-9773707, DMR-0210714

InSb films grown on GaAs exhibit a thickness-dependent electron mobility, which we determined to be due to scattering of free carriers from dislocations. Of particular importance in our work is that we showed that other factors, including surface and interface...

Structure-Property Correlations: Impurities in Semiconductors
Sponsor: National Science Foundation DMR-9975701, National Renewable Energy Laboratory ACQ-1-31619, Air Force of Scientific Research F49620-00-0328, Office of Naval Research N000-021-0899

In many semiconductors, the introduction of impurities at dilute concentrations leads to dramatic changes in the electronic, optical, and magnetic properties. For example, the introduction of a few percent nitrogen into GaAs leads to a band gap reduction of hundreds...

Structure-Property Correlations: Confined States in Nanostructures
Sponsor: Army Research Office DAAD 19-01-1-0462

Understanding electronic states in dimensionally-confined semiconductor structures is critical for technologies ranging from IR detection to quantum computation. Further advances in many applications will require a narrowing of the density of states, which may be achieved through an improved understanding...

Synthesis of Low-Dimensional Semiconductor Structures: Semiconductor Quantum Dots
Sponsor: National Science Foundation DMR-0210714 and CCF-0508225; Army Research Office DAAD 19-01-1-0462

Recently, strain-induced self-assembled quantum dots (QDs) have enabled the development of high-performance light-emitters and detectors. Further advances in optoelectronics and quantum computing will require a narrowing of the density of states and achievement of periodic charge distributions, both of which...

Synthesis of Low-Dimensional Semiconductor Structures: Directed Matrix-Seeding of Nanostructures
Sponsor: Radcliffe Fellowship, DCI Postdoctoral Fellowship HM1582-05-1-2027

Matrix-seeded growth is a promising approach for synthesis of luminescent semiconductor nanocomposites, consisting of nanocrystals in an amorphous matrix. In this approach, a supersaturated-layer is produced by high-energy ion-implantation, and annealing leads to nanocrystallization in the matrix. We recently synthesized...

Synthesis of Low-Dimensional Semiconductor Structures: Fabrication of Nanopillar Arrays
Sponsor: MRSEC SEED

We are currently exploring the seeded-assembly of semiconductor nanopillars on substrates topographically patterned using FIB. We have already seeded ordered arrays of holes with controlled concentrations of Ga droplets using FIB implantation. These holes have nearly uniform sizes and shapes....

Synthesis of Low-Dimensional Semiconductor Structures: Ion-Cut-Synthesis

Ion implantation plus thermal annealing often leads to the formation and coalescence of gas bubbles which may be used as the basis for integrating heterogeneous materials by means of transferring thin layers of one material onto another. For example, when...