Zuzanna Liliental-Weber graduated with a M.S. in Physics from Warsaw University, Poland and a Ph.D. in Solid State Physics in 1978 from the Institute of Physics, Polish Academy of Sciences. She has spent more than 4 years (1980-1984) as a Faculty Research Associate in Arizona State University, Tempe, AZ working on dark line defects in GaAs/AlGaAs light emitting diodes and interface roughness using different electron microscopy methods. She has been working at LBNL since 1984 and since 1994 she has been a senior staff scientist and a principal investigator in the Electronic Materials Program in the Materials Sciences Division.
Dr. Liliental-Weber’s work covers the area of structural defects in III-V semiconductor thin films and interfaces using state of the art transmission electron microscopy correlating the influence of these defects on the optical and electrical properties of the materials. Her interest includes p-doping, non-stoichiometry of semiconductor alloys and highly mismatched compound semiconductors. Her recent work on the effects of structural defects on cathodo- and photo-luminescence in the InxGa1-xN was featured in the covers of Physica Status Solidi. Her understanding of defect formation led to the application of specific defects for stress relaxation at the GaN and Si substrate interface. This method of defect induced improvement of structural perfection of the GaN layers was granted a U.S. patent in 2011. Dr. Liliental-Weber has published more than 400 papers in refereed journals and conference proceedings, review articles and book chapters.
• Z. Liliental-Weber, D.F. Ogletree, K.M. Yu, M. Hawkridge, J. Z. Domagala, and J. Bak-Misiuk, A.E. Berman, A. Emara, and S. Bedair, “Structural defects and cathodoluminescence of In x Ga1-xN layers,” phys. stat. sol. (c) 8(7-8), 2248-2250 (2011).
• Z. Liliental-Weber, M.E. Hawkridge, X. Wang, and A. Yoshikawa , “Structural differences in p-doped InN; indication of polytypism,” phys. stat. sol. (c) 7(7-8), 2025-2028 (2010).
• K. M. Yu, S. V. Novikov, R. Broesler, I. N. Demchenko, J. D. Denlinger, Z. Liliental-Weber, F. Luckert, R. W. Martin, W. Walukiewicz, and C. T. Foxon, “Highly mismatched crystalline and amorphous GaN1−xAsx alloys in the whole composition range,” J. Appl. Phys. 106, 103709 (2009).
• Z. Liliental-Weber, R.L. Maltez, J. Xie, and H. Morkoc, “Propagation of misfit dislocations from AlN/Si interface into Si,” J. Cryst. Growth 310, 3917-3923 (2008).
• D.N. Zakharov, Z.Liliental-Weber, B. Wagner, Z. J. Reitmeier, E. A. Preble, and R. F. Davis, “Structural TEM study of nonpolar a-plane gallium nitride grown on (11-20) 4H-SiC by organometallic vapor phase epitaxy,” Phys. Rev. B 71, 235334-42 (2005).
• Z. Liliental-Weber, T. Tomaszewicz, D. Zakharov, J. Jasinski, and M.A. O’Keefe, “Atomic Structure of Defects in GaN:Mg Grown with Ga Polarity,” Phys. Rev. Lett. 93, 206102 (2004).
• U.S. Patent No. 8,008,181, "Propagation of Misfit Dislocations from Buffer/Si Interface into Si," issued Aug. 30, 2011.
"Influence of structural defects on optical properties of semiconductor alloys"
Photo-and cathodo-luminescence (PL and CL) studies of thin (<100 nm) InGaN (10% In) films showed bandgap luminescence. Multiple luminescence peaks emerge in thicker films (>100 nm) when the electron beam is placed in the defective area, where transmission electron microscopy reveals high density of planar defects. This study strongly supports that these PL and CL peaks originate from defects with different atomic arrangement than the surrounding matrix.
"Orientation-patterned GaAs layers for infrared and terahertz frequency generation"
GaAs with regularly distributed inversion domains (alternative domains with Ga and As polarity) is a promising material for nonlinear optics for the generation of infrared and terahertz frequency. Transmission electron microscopy studies show formation of microtwins mainly in Ga-polar domains. These defects might be responsible of lower intensity of cathodoluminescence peak in these domains.
"GaNAs Highly Mismatched Alloys over the entire composition"
Alloying can lead to new properties of the material. Transmission electron microscopy showed that the highly mismatched GaN1-xAsx alloys can be obtained in the full range of composition with a large fraction of the compositions in the form of amorphous alloys. These films are homogeneous with well defined optical absorption edges and a monotonous change of the bandgap energy with the composition.
A high resolution TEM micrograph of a GaN1-xAsx layer with x=45% showing a “salt and pepper” contrast characteristic for an amorphous structure. This was confirmed by the diffraction pattern.