PROFESSOR

EDUCATION
B.S., University of Rochester (1968)
Ph.D., Brown University (1974)

FOCUS

My general research interests are in experimental studies of the optical and high-pressure properties of intrinsic and defect states in solids. Graduate students in my group perform Raman, photoluminescence, and other visible/infrared spectroscopies to probe vibrational and electronic excitations in tetrahedral semiconductors, III-V and II-VI heterostructures, and amorphous solids. Studies include the pressure (strain) dependence of these excitations,quantum well band offsets, and such impurities and point defects as atomic vacancies that can be strongly coupled to the crystalline lattice. Solid-solid phase transitions in bulk crystals and superlattices are also under investigation. Diamond-anvil pressure cells are used in many of the experiments, reaching pressures equivalent to those found halfway to the earth's center.

SELECTED PROJECTS

• Pressure studies of deep defect states in wide band gap semiconductors
  
• High pressure magneto-optical studies of novel localized states in compound semiconductors and their heterostructures
  
• Band offset determination in quantum wells by pressure optical measurements

PUBLICATIONS

• V. Iota and B. A. Weinstein. Effects of pressure on the Zn-vacancy in ZnSe. Phys. Rev. Lett. 81:4955­58 (1998).
• P. Perlin, V. Iota, B. A. Weinstein, P. Wisniewski, T. Suski, M. Osinski, and P. G. Eliseev. Influence of pressure on the photoluminescence and electroluminescence of GaN/InGaN/AlGaN quantum wells. Appl. Phys. Lett. 70:2993­95, (1997).
• T. M. Ritter, B. A. Weinstein, R. M. Park, and M. C. Tamargo. Emergence of deep levels in n-Type ZnSe under hydrostatic pressure. Phys. Rev. Lett. 76:964­67 (1996).
• R. J. Chen and B. A. Weinstein. New diamond-anvil cell design for far infrared magnetospectroscopy featuring in situ cryogenic pressure tuning. Rev. Sci. Intrum. 67:2883­89 (1996).
  
• B. A. Weinstein, T. M. Ritter, D. Strachan, M. Li, H. Luo, M. Tamargo, and R. Park. Competition of deep and shallow impurities in wide-gap II-VI semiconductors under pressure. Phys. Stat. Sol. (b) 198:167­80 (1996).

Fig. 1 Proposed model explaining the pressure behavior of the broad "midgap" PL bands (BB) observed in ZnSe, showing the PL transitions at (a) 1 atm, (b) 20 kbar, and (c) 60 kbar.