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Steigerwald, Andrew
Ph.D. in Interdisciplinary Materials Science, August 2010

Research Information

Ph.D. Dissertation
Measuring Point Defects in Semiconductors Using Coherent Acoustic Phonon Spectroscopy

Ph.D. Advisor
Norman Tolk, Physics

Ph.D. Committee
Sandra Rosenthal, Chemistry
Jim Davidson, Electrical Engineering
Kalman Varga, Physics
Richard Mu, Fisk University


Abstract. The operation and properties of semiconductor devices depends critically on a materials electronic structure. Point defects, such as vacancy and interstitial defects that arise from operation in radiative atmospheres or during less-than-ideal growth processes, have a significant influence on electronic material properties and tend to degrade device operation. Here we show that a novel ultrafast time-resolved pump-probe technique, known as coherent acoustic phonon spectroscopy, is capable of non-destructive, quantitative, depth-dependent measurement of point defect profiles arising from ion irradiation in gallium arsenide. In the CAP response, defects are observable through reduction of the CAP oscillation amplitude, which is demonstrated to be connected to a decrease in the photoelastic constant at the 1.42 eV GaAs band-edge caused by defect-induced lattice strain. Finally, we present theoretical calculations that support our proposed model and agree well with experimental observations.

Selected Publications

Mechanical and electronic properties of ferromagnetic Ga1-xMnxAs using ultrafast coherent acoustic phonons. Qi, J; Yan, JA; Park, H; Steigerwald, A; Xu, Y; Gilbert, SN; Liu, X; Furdyna, JK; Pantelides, ST; Tolk, N, PHYSICAL REVIEW B, 81, 115208 , (2010)

Semiconductor point defect concentration profiles measured using coherent acoustic phonon waves. Steigerwald, A; Xu, Y; Qi, J; Gregory, J; Liu, X; Furdyna, JK; Varga, K; Hmelo, AB; Lupke, G; Feldman, LC; Tolk, N, APPLIED PHYSICS LETTERS, 94, 111910 , (2009)

Ultrafast laser-induced coherent spin dynamics in ferromagnetic Ga1-xMnxAs/GaAs structures. Qi, J; Xu, Y; Steigerwald, A; Liu, X; Furdyna, JK; Perakis, IE; Tolk, NH, PHYSICAL REVIEW B, 79, 085304 , (2009)

Compositional analysis of lead telluride films deposited via pulsed electron-beam ablation. Steigerwald, A; Aga, R; Collins, WE; Mu, R; Hmelo, AB, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, 26, 513-516 , (2008)

Er-doped ZnO films grown by pulsed e-beam deposition. Pan, Z; Morgan, SH; Ueda, A; Aga, R; Steigerwald, A; Hmelo, AB; Mu, R, JOURNAL OF PHYSICS-CONDENSED MATTER, 19, 266216 , (2007)

Vanderbilt University