Selected Publications

by Joachim Piprek and collaborators (ordered by topic)

• light-emitting diodes
• edge-emitting laser diodes
• vertical-cavity laser diodes
• semiconductor optical amplifiers
• electro-absorption modulators
• photodiodes
• solar cells
• micro-coolers
• optoelectronic integrated circuits
• semiconductor material properties

Citation ranking at Google Scholar

• Simulation-based Machine Learning for Optoelectronic Device Design: Perspectives, Problems, and Prospects, J. Piprek, Opt Quant Electron 53, 175 (2021)
• Efficiency Models for GaN-based Light Emitting Diodes: Status and Challenges, J. Piprek, MDPI Materials 13, 5174 (2020) (invited)
• Energy Efficiency Analysis of GaN-based Blue Light Emitters, J. Piprek, ECS Journal of Solid State Science and Technology 9, 015008 (2020) (invited)
• What limits the efficiency of GaN-based superluminescent light-emitting diodes (SLEDs)?, J. Piprek, Opt. Quant. Electron. 51:382 (2019)
• Enhanced electroluminescent cooling in GaN-based light-emitting diodes; J. Piprek & Z. M. Li, Proc. SPIE 10107, 101070X (2017)
• Electroluminescent cooling mechanism in InGaN/GaN light-emitting diodes, J. Piprek & Z. M. Li, Opt. Quant. Electron. 48:472 (2016)
• Comparative efficiency analysis of GaN-based light-emitting diodes and laser diodes, J. Piprek, Appl. Phys. Lett. 109, 021104 (2016)
• How to decide between competing efficiency droop models for GaN-based light-emitting diodes, J. Piprek, Appl. Phys. Lett. 107, 031101 (2015)
• GaN-based bipolar cascade light-emitting diode with 250% peak quantum efficiency, J.Piprek, Optical and Quantum Electronics 47, 1305 (2015)
• On the uncertainty of the Auger recombination coefficient extracted from InGaN/GaN light-emitting diode efficiency droop measurements, J. Piprek, F. Roemer, and B. Witzigmann, Appl. Phys. Lett. 106, 101101 (2015)
• An LED with 250% peak quantum efficiency, J. Piprek, SPIE Newsroom, 24. Feb. 2015 (invited)
• LED droop: a critical review and novel solution, J. Piprek, Compound Semiconductor 20, 44-49, July 2014 (invited review)
• Blue light emitting diode exceeding 100% quantum efficiency, J. Piprek, Phys. Status Solidi Rapid Research Letters 8, 424 (2014)
• Origin of InGaN/GaN light-emitting diode efficiency improvements using tunnel-junction-cascaded active regions, J. Piprek, Applied Physics Letters 104, 051118 (2014)
• III-Nitride LED Efficiency Droop Models: A Critical Status Review; J. Piprek, Proc. NUSOD-13, pp. 107-108 (2013).
• "Sensitivity analysis of electron leakage in III-nitride light-emitting diodes," J. Piprek and S. Li, Appl. Phys. Lett. 102, 131103 (2013)
• "Origin of InGaN light-emitting diode efficiency improvements using chirped AlGaN multi-quantum barriers," J. Piprek and S. Li, Appl. Phys. Lett. 102, 023510 (2013)
• "AlGaN polarization doping effects on the efficiency of blue LEDs," J. Piprek, Proc. SPIE 8262, 8262oE (2012)
• "Ultra-violet light-emitting diodes with quasi acceptor-free AlGaN polarization doping," J. Piprek, Optical and Quantum Electronics (2012) 44:67–73
• “Unified Model for the GaN LED Efficiency Droop,” J. Piprek, Proc. SPIE 7939, 793916 (2011)
• “Electron Leakage Effects on GaN-based Light-Emitting Diodes,” J. Piprek and S. Li, Optical and Quantum Electronics 42, 89-95 (2010)
• " Efficiency droop in nitride-based light-emitting diodes," Joachim Piprek; Phys. Status Solidi A 207, No. 10, 2217-2225 (2010) - invited feature artice
• " Origin of efficiency droop in GaN-based light-emitting diodes," Min-Ho Kim, Martin F. Schubert, Qi Dai, Jong Kyu Kim, E. Fred Schubert, Joachim Piprek, and Yongjo Park; Appl. Phys. Lett. 91, 183507 (2007)
• "GaN-based Light Emitting Diodes" J. Piprek and S. Li, Chapter 10 in: Optoelectronic Devices: Advanced Simulation and Analysis, ed. by J. Piprek, Springer Verlag, New York, 2005.
• "Internal Efficiency Analysis of 280 nm Light Emitting Diodes," J. Piprek, C. Moe, S. Keller, S. Nakamura, and S. P. DenBaars, in: Physics and Applications of Optoelectronic Devices, SPIE Proc. 5594-28, 2004.
• "3D Simulation and Analysis of AlGaN/GaN Ultraviolet Light Emitting Diodes," Joachim Piprek, Tom Katona, Steven P. DenBaars, and Simon Li, in: Light-Emitting Diodes: Research, Manufacturing and Applications VIII, Photonics West 2004, SPIE Proc. 5366-59.

• GaN-based Bipolar Cascade Lasers with 25 nm wide Quantum Wells, J.Piprek, G. Muziol, M. Siekacz, C. Skierbiszewski, Opt. Quant. Electron. 54: 62 (2022)
• On the Reliability of Pulse Power Saturation Models for Broad-Area GaAs-based Lasers, J. Piprek, Opt. Quant. Electron. 51:60 (2019)
• "What Causes the Pulse Power Saturation of GaAs-Based Broad-Area Lasers?," J. Piprek & Z. M. Li; IEEE Photonics Technology Letters Vol. 30, No. 10, 963-966 (2018).
• Internal power loss in GaN-based lasers: Mechanisms and remedies, J. Piprek, Opt. Quant. Electron. 49 (2017) 329
• What is to blame for the low energy efficiency of GaN-based lasers? J. Piprek, Compound Semiconductor Magazine vol. 23, no. 5, pp. 34-38 (2017)
• "What limits the power conversion efficiency in GaN-based lasers?"; J. Piprek, Proc. SPIE 10098, 100980Q (2017)
• "What limits the efficiency of high-power InGaN/GaN lasers?," J. Piprek, Journal of Quantum Electronics vol. 53, no. 2, p. 2000104 (2017)
• "Analysis of efficiency limitations in high-power InGaN/ GaN laser diodes," J. Piprek, Opt. Quant. Electron. 48, 471 (2016)
• "Index-antiguiding in narrow-ridge GaN-based laser diodes", L. Redaelli, H. Wenzel, J. Piprek, Th. Weig, S. Einfeldt, M. Martens, G. Lükens, U. T. Schwarz, and M. Kneissl, Journal of Quantum Electronics 51, 2000506 (2015)
• "On the importance of non-thermal far-field blooming in broad-area high-power laser diodes," J. Piprek and Z.M.S.Li; Appl. Phys. Lett. 102, 221110 (2013).
• "Inverse Thermal Lens Effects on the Far Field Blooming of Broad Area Laser Diodes," J. Piprek; IEEE Photonics Technology Letters Vol. 25, No. 10, 958-960(2013).
• "Simulation of laser diodes with nonpolar InGaN multi-quantum-wells," Z. Q. Li, Z. M. Li, and J. Piprek, Physica Status Solidi C 7, No. 7-8, 2259-2261 (2010)
• "Analysis of wavelength-dependent performance variations of GaN-based ultraviolet lasers," J. Piprek, H. Wenzel, and M. Kneissl, Proc. SPIE 6766, 67660H (2007)
• “Blue Laser Diodes,” J. Piprek (invited), Optik & Photonik, vol. 1, no. 2, pp. 52-55, 2007.
• "Physics of High-Power InGaN/GaN Lasers", Joachim Piprek and Shuji Nakamura, IEE Proceedings, Optoelectronics, vol. 149, No. 4, pp. 145-151, August 2002.
• "Analog Modulation of Semiconductor Lasers," J. Piprek and J. E. Bowers, Chapter 3 in RF Photonic Technology in Optical Fiber Links, ed. W. Chang, Cambridge University Press, 2002.
• "What limits the maximum output power of long-wavelength AlGaInAs lasers ?" J. Piprek, K. White, and A. SpringThorpe, IEEE Journal of Quantum Electronics, vol. 38, no. 9, pp. 1253-1259, September 2002.
• "Advanced analysis of high-temperature failure mechanisms in telecom lasers," J. Piprek; Proc. SPIE 4533, 70 (2001).
• "Simulation and optimization of 420nm InGaN/GaN laser diodes," J. Piprek, R. Kehl Sink, Monica A. Hansen, John E. Bowers, and Steve P. DenBaars; Proc. SPIE 3944, 28 (2000).
• "Self-Consistent Analysis of High-Temperature Effects on Strained-Layer Multi-Quantum Well InGaAsP/InP Lasers", Joachim Piprek,  Patrick Abraham, and John E. Bowers, IEEE Journal of Quantum Electronics, vol. 36, no. 3, pp. 366-374,  March 2000.
• "Cavity Length Effects on Internal Loss and Quantum Efficiency of Multi-Quantum-Well Lasers," J. Piprek, P.Abraham and J. E. Bowers, IEEE Journal of Selected Topics in Quantum Electronics, Special Issue on Semiconductor Lasers, vol. 5, no. 3, pp. 643-647 (1999).
• "Carrier Non-Uniformity Effects on the Internal Efficiency of Multi-Quantum Well Lasers,"J. Piprek, P.Abraham and J. E. Bowers, Applied Physics Letters, vol. 74, no. 4, pp. 489-491 (1999).
• "Improvement of Internal Quantum Efficiency in 1.55 µm Laser Diodes with InGaP Electron Stopper Layer," Patrick Abraham, Joachim Piprek, Steven P. DenBaars and John E. Bowers, Japanese Journal of Applied Physics,  Part 1, vol. 38,  no. 2B, pp. 1239-42 (1999).
• "The Microstrip Laser," D. Tauber, M. Horita, J. Piprek,  P. Abraham, A. L. Holmes, and J. E. Bowers, IEEE Photonics Technology Letters, vol. 10, pp. 478-480 (1998).
• "InGaAsP/InP DCPBH Laser Diode with Asymmetric Waveguide for 1.3-micron wavelength," W. Both, H. Bachert, A. Knauer, J. Piprek, W. Pittroff, R. Puchert, R. Rimpler, U. Schade, R. Staske, K. Vogel, G. Wagner, and U. Zeimer, Physica Status Solidi (a), Vol. 125, pp. 749-758 (1991).
• "Thermal Resistance of InGaAsP/InP Laser Diodes," W. Both and J. Piprek, Journal of Thermal Analysis, Vol. 36, pp. 1441-1456 (1990).

Vertical-Cavity Surface-Emitting Lasers

• GaN-based vertical-cavity laser performance improvements using tunnel-junction-cascaded active regions, J. Piprek, Applied Physics Letters 105, 011116 (2014)
• What is the Problem with GaN-based VCSELs ?; J. Piprek; Proc. NUSOD-13, pp. 89-90 (2013).
• "GaN-based VCSELs: Analysis of internal device physics and performance limitations," J. Piprek and Z. M. Li, Proc. SPIE 7602, 760217 (2010)
• “Electronic Properties of InGaN/GaN Vertical Cavity Lasers”, J. Piprek, S. Li, R. Farrell, S. P. DenBaars, and S. Nakamura, Ch. 19 in: Nitride Semiconductor Devices – Principles and Simulation, ed. by J. Piprek (Wiley, 2007)
• "Effects of Built-In Polarization on InGaN/GaN Vertical-Cavity Surface-Emitting Lasers," Joachim Piprek, Robert Farrell, Steve DenBaars, and Shuji Nakamura, IEEE Photonics Technology Letters, vol. 18, no. 1, pp. 7-9, 2006.
• "Temperature dependence of the relaxation resonance frequency of long-wavelength vertical-cavity lasers," ES Bjorlin, J Geske, M Mehta, J Piprek, JE Bowers, IEEE Photonics Technology Letters, vol. 17, no. 5, pp. 944-946, 2005.
• "Failure Analysis of GaN-Based Current-Injected Vertical-Cavity Surface-Emitting Lasers", J. Piprek, in: Optoelectronic Devices: Physics, Fabrication, and Application II , SPIE Proc. 6013-12, 2005.
• "Vertical-cavity surface-emitting laser active regions for enhanced performance with optical pumping," J Geske, KG Gan, YL Okuno, J Piprek, JE Bowers, J. Quantum Electron. 40, 1155-1162, 2004.
• "Design and Optimization of High-Performance 1.3 µm VCSELs," Joachim Piprek, Manish Mehta, and Vijay Jayaraman, in: Physics and Simulation of Optoelectronic Devices XII, SPIE Proc. 5349, 2004.
• "High-power 1320-nm wafer-bonded VCSELs with tunnel junctions," Jayaraman, V.; Mehta, M.; Jackson, A.W.; Wu, S.; Okuno, Y.; Piprek, J.; Bowers, J.E.; Photonics Technology Letters, IEEE , Volume: 15 Issue: 11 , Page(s): 1495 -1497, 2003.
• "Electro-Thermal Analysis of Oxide-Confined Vertical-Cavity Lasers," Joachim Piprek, physica status solidi (a), Volume 188, Issue 3, pp. 905-912, December 2001.
• "1.55-micron vertical-cavity laser arrays for wavelength-division multiplexing ," Karim, A.; Piprek, J.; Abraham, P.; Lofgreen, D.; Yi-Jen Chiu; Bowers, J.E., IEEE Journal on Selected Topics in Quantum Electronics , Volume: 7 Issue: 2 , Mar/Apr 2001, Page(s): 178 -183
• "Harmonic Distortion in 1.55-micron Vertical-Cavity Lasers," J. Piprek, K. Takiguchi, K. A. Black, E. L. Hu, and J. E. Bowers, IEEE Photonics Technology Letters, Vol. 12, No. 12, pp. 1686-88, December 2000.
• "Long-Wavelength Vertical-Cavity Lasers," D. I. Babic, J. Piprek, and J. E. Bowers, Chapter 9 in Vertical Cavity Surface Emitting Lasers, ed. by C. Wilmsen, H. Temkin,and L. A Coldren, Cambridge University Press, 1999.
• "Analog Modulation of 1.55-micron Vertical-Cavity Lasers," Joachim Piprek, Koichi Takiguchi, Alexis Black, Patrick Abraham, Adrian Keating, Volkan Kaman , Sheng Zhang, and John E. Bowers, SPIE Proc. Vol. 3627, pp. 119-127, "Vertical-Cavity Surface-Emitting Lasers III," eds. K. D. Choquette and C. Lei (1999).
• "Cryogenic Performance of Double-Fused 1.5-micron Vertical-Cavity Lasers," Y. M. Zhang, J. Piprek,  N.Margalit, M.Anzlowar, and J.E. Bowers, IEEE Journal of Lightwave Technology, vol. 17, no. 3, pp. 503-508 (1999).
• "Minimum Temperature Sensitivity of 1.55-micron Vertical-Cavity Lasers at -30nm Gain Offset," J. Piprek, Y.A.Akulova, D.I.Babic, L.A.Coldren, and J.E.Bowers, Applied Physics Letters, vol. 72, no. 15, pp. 1814-1816 (1998).
• "Temperature Sensitivity of 1.54um Vertical Cavity Lasers with an InP-based Bragg Reflector," S. Rapp, J. Piprek, K. Streubel, J. André, and J. Wallin, IEEE Journal of Quantum Electronics, vol. 33, no. 10, pp. 1839-1845 (1997).
• "Simulation and Analysis of 1.55-micron Double-Fused Vertical-Cavity Lasers," J. Piprek, D. I. Babic, and J. E. Bowers, Journal of Applied Physics, Vol. 81, pp. 3382-3390 (1997).
• "Numerical analysis of 1.54 um double-fused vertical-cavity lasers operating continuous-wave up to 33C," J. Piprek, D. I. Babic, and J. E. Bowers, Applied Physics Letters, Vol. 68, pp. 2630-2632 (1996).
• "Modeling light vs. current characteristics of long-wavelength VCSELs with various DBR materials," J. Piprek, H. Wenzel, H-J Wuensche, D. Braun, F. Henneberger, SPIE Proc. 2399, 605 (1995).
• "Thermal Comparison of Long-Wavelength Vertical-Cavity Surface-Emitting Laser Diodes," J. Piprek and S. J. B. Yoo, Electronics Letters, Vol. 30, pp. 866-868 (1994).
• "Modeling Thermal Effects on the Light vs. Current Characteristic of Gain-Guided Vertical-Cavity Surface-Emitting Lasers," J. Piprek, H. Wenzel, and G. Sztefka, IEEE Photonics Technology Letters, Vol. 6, pp. 139-142 (1994).

Semiconductor Optical Amplifiers

• "Broadband Rate-Equation Model including Many-Body Gain for WDM Traveling-Wave SOAs," V. Lal, W. Donat, A. Tauke Pedretti, L. Coldren, D. Blumenthal, and J. Piprek; in: Proc. IEEE/LEOS Int. Conf. Numerical Simulation of Optoelectronic Devices (NUSOD), Berlin, Germany, 2005.
• "High-temperature characteristics and tunability of long-wavelength vertical-cavity semiconductor optical amplifiers," Kimura, T.; Bjorlin, S.; Piprek, J.; Bowers, J.E.; Photonics Technology Letters, IEEE , Volume: 15 Issue: 11 , Page(s): 1501 -1503, Nov. 2003.
• "Vertical-cavity amplifying modulator at 1.3 micron," Bjorlin, E.S.; Dahl, A.; Piprek, J.; Abraham, P.; Chiu, Y.-J.; Bowers, J.E. IEEE Photonics Technology Letters , Volume: 13 Issue: 12 , Dec. 2001 Page(s): 1271 -1273
• "1.3-micron vertical-cavity amplifying switch," E. Staffan Björlin, Joachim Piprek, Sangyoun Gee, Yi-Jen Chiu, John E. Bowers, Andres Dahl, Patrick Abraham, “Optical Amplifiers and Their Applications”, OSA Trends in Optics and Photonics, vol. 60, 2001.
• "Optical Gain-Bandwidth Product of Vertical-Cavity Laser Amplifiers," J. Piprek, E. S. Bjorlin, and J. E. Bowers, Electronics Letters, Volume: 37 Issue: 5 , March 2001 Page(s): 298 -299
• "Design and Analysis of Vertical-Cavity Semiconductor Optical Amplifiers," J. Piprek, S. Bjorlin, and J. E. Bowers, IEEE Journal of Quantum Electronics, Vol. 37, No. 1, pp.127-134, January 2001.
• "1.3-um Vertical-Cavity Amplifier," ES Bjorlin, B Riou, A Keating, P Abraham, YJ Chiu, J Piprek, JE Bowers; IEEE Phot. Technol. Lett. 12 (8), 951-953 (2000)

Electro-Absorption Modulators

• "Nonlinear Properties of Traveling-Wave Electroabsorption Modulator," Shim, J.; Liu, B.; Piprek, J.; Bowers, J.E.; IEEE Photonics Technology Letters, Volume: 16 , Issue: 4 , April 2004, Pages:1035 - 1037
• "Slope Efficiency and Dynamic Range of Traveling-Wave Multiple-Quantum-Well Electroabsorption Modulators," Bin Liu, Jongin Shim, Yi-jen Chiu, Hsu Feng Chou, Joachim Piprek, and John E. Bowers, IEEE Phot. Technol. Lett., vol. 6, no. 2 pp. 590-592 (2004).
• "Analog characterization of low-voltage MQW traveling-wave electroabsorption modulators," Bin Liu; Jongin Shim; Yi-Jen Chiu; Keating, A.; Piprek, J.; Bowers, J.E.; IEEE J. Lightwave Technology, Volume: 21 , Issue: 12 , Pages:3011 - 3019 ( 2003).
• "High-Efficiency Multi-Quantum-Well Electroabsorption Modulators", J. Piprek, Y.-J. Chiu, S. Zhang, J. E. Bowers, C. Prott, and H. Hillmer, in: Integrated Optoelectronics, ECS Proc. 2002-4, 139-149 ( 2002).
• "Analysis of Multi-Quantum Well Electroabsorption Modulators" J. Piprek, Yi-Jen Chiu, and J. E. Bowers, SPIE Proc. 4646-77, Physics and Simulation of Optoelectronic Devices X, Photonics West, San Jose, January 2002.

Photodetectors

• "Optimization of GaAs Amplification Photodetectors for 700% Quantum Efficiency" J. Piprek, D. Lasaosa, D. Pasquariello, and J. E. Bowers, IEEE Journal of Selected Topics in Quantum Electronics, Issue on Optoelectronic Device Simulation, Vol. 9, No. 3, 2003.
• "InP-based Waveguide Photodetector with Integrated Photon Multiplication," D. Pasquariello, J. Piprek, D. Lasaosa, and J. E. Bowers, SPIE-ITCom Symp. Semiconductor Optoelectronic Devices for Lightwave Communication, Orlando, SPIE Proc. 5248-34 (2003).
• "Novel Waveguide Photodetectors on InP with Integrated Light Amplification," J. Piprek, D. Pasquariello, D. Lasaosa, and J. E. Bowers: in Compound Semiconductors, ECS Proc. 2003-04, pp. 1-8, 2003
• "Physics of Waveguide Photodetectors with Integrated Amplification", J. Piprek, D. Lasaosa, D. Pasquariello, and J. E. Bowers, in: Physics and Simulation of Optoelectronic Devices XI, SPIE Proc. 4986-28, January 2003.

• "InP solar cell improvement by inverse delta-doping ," J. Piprek and K. W. Boer, Proc. 24th IEEE Photovoltaic Specialist Conf., Vol. 2, pp. 1818-1821 (1994).
• "Inverse Delta-Doping for Improvement of Solar Cells," K. W. Böer and J. Piprek, Journal of Applied Physics, Vol. 75, pp. 5095-5101 (1994).
• "Donor-Acceptor Pairs to Limit V_oc-Improvement of Photo Diodes," K. W. Böer and J. Piprek, Solar Energy Materials and Solar Cells, Vol. 32, pp. 395-403 (1994).

Micro-Coolers

• "Electroluminescent cooling mechanism in InGaN/GaN light-emitting diodes", J. Piprek & Z. M. Li, Opt. Quant. Electron. 48 (2016) 472
• "Superlattice Microrefrigerators Fusion Bonded With Optoelectronic Devices," Yan Zhang, Gehong Zeng, Joachim Piprek, Avram Bar-Cohen and Ali Shakouri, IEEE Trans. Compon. Packag. Technol., vol. 28, no. 4, pp. 658-666, December 2005.
• "Thermionic Emission Cooling in Single Barrier Heterostructures," A. Shakouri, C. LaBounty, J. Piprek, P. Abraham, and J. Bowers, Applied Physics Letters, Vol. 74, No. 1, pp. 88-90 (1999).

Optoelectronic Integrated Circuits

• "Monolithic Wavelength Converter: Many-Body Effects and Saturation Analysis" J. Piprek, S. Li, P. Mensz, and J. Hader, Chapter 14 in: Optoelectronic Devices - Advanced Simulation and Analysis, ed. by J. Piprek, Springer Verlag, New York, 2005.
• "Device Physics of an Optoelectronic Integrated Wavelength Converter," J. Piprek, V. Lal, J. Hutchinson, A. Tauke Pedretti, M. Dummer, and L. Coldren, in: Optoelectronic Integrated Circuits IX, SPIE Proc. 5729, 2005.
• "Sampled-grating DBR lasers: Calibrated 3D simulation of tuning characteristics," L. Schneider, M. J. Pfeiffer, J. Piprek, A. Witzig, B. Witzigmann, in: Optoelectronics and Photonic Devices, SPIE Proc. 5825, 2005.
• "Saturation Analysis of a Monolithic Wavelength Converter," Joachim Piprek, John Hutchinson, Jeffrey Henness, Milan Masanovic, and Larry A. Coldren, SPIE Proc. 5594, 102, 2004.

Semiconductor Material Properties

• "Recombination in polar InGaN/GaN LED structures with wide quantum wells", Jens W. Tomm, Artem Bercha, Grzegorz Muziol, Joachim Piprek, Witold Trzeciakowski, PSS Rapid Research Letters (2023)
• "On the uncertainty of the Auger recombination coefficient extracted from InGaN/GaN light-emitting diode efficiency droop measurements", J. Piprek, F. Roemer, and B. Witzigmann, Appl. Phys. Lett. 106, 101101 (2015)
• "AlGaN/AlN distributed Bragg reflectors for deep ultraviolet wavelengths," Craig G. Moe, Yuan Wu, Joachim Piprek, Stacia Keller, James S. Speck, Steven P. DenBaars, and David Emerson, phys. stat. sol. (a) 203, No. 8, pp. 1915–1919 (2006)
• "Selective undercut etching of InGaAs and InGaAsP quantum wells for improved performance of long-wavelength optoelectronic devices," Pasquariello, D.; Bjorlin, E.S.; Lasaosa, D.; Chiu, Yi.-J.; Piprek, J.; Bowers, J.E. ; Journal of Lightwave Technology, v 24, n 3, March 2006, p 1470-7
• "Thermal Conductivity Reduction in GaAs/AlAs Distributed Bragg Reflectors," J. Piprek, T. Troger, B. Schroter, J.Kolodzey, and C.S.Ih, IEEE Photonics Technology Letters,  Vol. 10,  No. 1, pp.81-83 (1998).
• "Wafer fused p-InP/p-GaAs heterojunctions," F. Salomonsson, K. Streubel, J. Bentell, M. Hammar, D. Keiper, and R. Westphalen, J. Piprek, L. Sagalowicz, A. Rudra, and J. Behrend, J. Appl. Phys.,  Vol. 83,  No. 2, pp.768-774 (1998).
• "Band gap bowing and refractive index spectra of polycrystalline AlInN films deposited by sputtering," T. Peng, J.Piprek, G. Qiu, J.O. Olowolafe, K.M. Unruh, C.P.Swann, and E. F. Schubert, Applied Physics Letters, Vol. 71, no. 17, pp. 2439-2441 (1997).
• "Refractive Index of AlGaInN Alloys," T. Peng and J. Piprek, Electronics Letters, Vol. 32, pp. 2285-2286 (1996).
• "Material Parameters of Quaternary III-V Semiconductors for Multilayer Mirrors at 1.55-micron Wavelength," M. Guden and J. Piprek, Modeling and Simulation in Materials Science and Engineering, Vol. 6, pp. 349-357 (1996).
• "Deep-Level Delta-Doping of Ti in GaAs: Modeling of Tunnel-Assisted Recombination," J. Piprek and A. Schenk, Journal of Applied Physics, Vol. 73, pp. 456-458 (1993).
• "Ti Deep-Level Delta-Doping in GaAs Schottky Diodes: Capacitance-Voltage Analysis," J. Piprek, P. Krispin, H. Kostial, C. H. Lange, and K. W. Böer, Physica Status Solidi (b), Vol. 173, pp. 661-670 (1992).
• "Thermal Resistance of Ridge-Waveguide Laser Diodes Based on GaAs, GaSb or InP," W. Both and J. Piprek, Journal of Thermal Analysis, Vol. 37, pp. 61-71 (1991).