Biographical Information

• Dr.rer.nat.(Physics), Universitat Regensburg, Germany, 1989
• Diploma in Physics, Universitat Regensburg, Germany, 1982

Honors and Awards

• Erskine Fellow, University of Canterbury, Christchurch, NZ, 1997
• Feodor-Lynen Fellow, Alexander von Humboldt Foundation, 1989

Research Interests

Our research is focused on experimental studies of dynamical processes in condensed matter. Current interests include charge transport in ferroelectric and photorefractive solids, energy transfer in luminescent materials, relaxation of molecular impurities, spectroscopy of semiconductors, and time-resolved x-ray scattering.

Collaborations exist with universities, National Laboratories and industry within the US and with research groups in The Netherlands, Germany, Russia, and New Zealand.

Recent Publications

S. M. Loureiro, A. Setlur, W. Heward, S. Taylor, H. Comanzo, M. Monoharan, A. Srivastava, P. Schmidt, and U. Happek; First  observation of quantum splitting behavior in nanocrystalline SrAl₁₂O₁₉:Pr, Mg  phosphor. Chemistry of Materials 17(2005) 3108.

J.K. Krebs and U. Happek; Optical Spectroscopy of Trivalent Chromium in Sol-Gel Lithium Niobate. Applied Physics Letters 87, (2005) 251910. 

V. Venkatasamy, N. Jayajaru,  S.M. Cox, U. Happek, J.L. Stickney; Optimization of CdTe nanofilm formation by electrochemical atomic layer epitaxy (EC-ALE). Journal of Applied Electrochemistry 36 (11) (2006) 1223.

D. Mihalcea, C.L. Bohn, U. Happek, and P. Piot; Lomgitudinal electron bunch diagnostic using coherent transition radiation. Phys. Rev., Accelerators and Beams 9 (8) (2006) 082801.

J. Grimm, J. Fleniken, K.W. Krämer, D.Biner, U. Happek, and H.U. Güdel; On the determination of photoionization thresholds of Ce³⁺ doped Cs₃LuCl₆, Cs₂LiLuCl₆ and Cs₂LiYCl₆ by thermoluminescence. Journal of Luminescence (2006).

U.Happek and G.M. Salley;  Photoionization  Energies of Cr³⁺ in LiNbO₃. Journal of Luminescence 125 (2006) 104.

A.A. Setlur, A.M. Srivastava, H.L. Pham, M.E. Hannah, and U. Happek; Charge creation, trapping and long phosphorescence in Sr₂MgSi₂O₇:Eu²⁺, RE³⁺. Journal of Applied Physics 103 (2008) 053153.

 ‪A.M. Srivastava, U. Happek, and P. Schmidt, Luminescence of LuCl₃:Pr³⁺ under interconfigurational (4f² ® 4f¹5d¹) and band gap excitation . Optical Materials 31 (2008) 213.

A.A. Setlur, J.J. Shiang, and+ U. Happek; Eu²⁺ - Mn²⁺ phosphor saturation in 5 mm light emitting diode lamps.  Applied Physics Letters 92 (2008) 081104.

D.O. Banga, R. Vaidyanathan, L. Xuehai, J.L. Stickney, S. Cox, and U. Happek; Formation of PbTe nanofilms by electrochemical atomic layer deposition (ALD).Electrochimica Acta 53 (2008) 6988-6994.

A.A. Setlur, W.J. Heward, M.E. Hannah, and U. Happek; Incorporation of Si⁴⁺ - N^3- into Ce³⁺ doped garnets for warm white LED phophors. Chem. Mater. 20 (2008) pp. 6277 - 6283.

A.M. Srivastava, A.A. Setlur, H.A Comanzo, M.E. Hannah, P.A. Schmidt, and U. Happek; Luminescence from the Pr³⁺ 4f¹5d¹ and ¹S₀ states in LiLaP₄O₁₂. Journal of Luminescence 129 (2009) 126.

A.M. Srivastava,  J.S. Vartuli, S.J. Duclos, S.B. Chaney, P.A. Schmidt, and U. Happek; Luminescence Pr³⁺ doped  LuCl₃ and LuBr₃ under intraconfigurational (4f²> 4f¹5d¹) and band gap excitation.  IEEE Transactions on Nuclear Science 56 (2009) 986.

‪U. Happek, A.A, Setlur, and J.J. Shiang; Inverse bottleneck in Eu²⁺ - Mn²⁺ energy transfer.  Journal of Luminescence 129 (2009) 1459 -1463.

‪A.M. Srivastava, H.A. Comanzo, S. Camardello, S.B. Chaney, M. Aycibin, and U. Happek; Unusual luminescence of octahedrally coordinated divalent europium in Cs₂M²⁺P₂O₇ (M²⁺ = Sr, Ca). J. Lumin. 129 (2009) 919-925.

 A.A. Setlur, U. Happek;  Cerium luminescence in nd⁰ perovskites. Journal of Solid State Chemistry, Volume 183, (2010) 1127-1132.

A.M. Srivastava, S.J. Camardello, H.A. Comanzo, M. Aycibin, U. Happek;  Explanation for the variance of the Ce³⁺ emission energy in LnI₃ [Ln = Lu³⁺, Y³⁺, Gd³⁺]. Optical Materials 32 (2010)  936-940.

A.A. Setlur, E.V. Radkov, C.S. Henderson, J.H. Her, A.M. Srivastava, N. Karkada, M.S. Kishore, N.P. Kumar, D. Aesram, A. Deshpande, B. Kolodin, L.S. Grigorov, and U. Happek; Energy-Efficient, High-Color-Rendering LED Lamps Using Oxyfluoride and Fluoride Phosphors. Chemistry of Materials 22 (2010) 4076-4082.