@article{berkman_el-masry_emara_bedair_2008, title={Nearly lattice-matched n, i, and p layers for InGaN p-i-n photodiodes in the 365-500 nm spectral range}, volume={92}, ISSN={["0003-6951"]}, DOI={10.1063/1.2896648}, abstractNote={We report on nearly lattice-matched grown InGaN based p-i-n photodiodes detecting in the 365–500nm range with tunable peak responsivity tailored by the i-layer properties. The growth of lattice matched i- and n-InGaN layer leads to improvement in the device performance. This approach produced photodiodes with zero-bias responsivities up to 0.037A∕W at 426nm, corresponding to 15.5% internal quantum efficiency. The peak responsivity wavelength ranged between 416 and 466nm, the longest reported for III-N photodiodes. The effects of InN content and i-layer thickness on photodiode properties and performance are discussed.}, number={10}, journal={APPLIED PHYSICS LETTERS}, author={Berkman, E. A. and El-Masry, N. A. and Emara, A. and Bedair, S. M.}, year={2008}, month={Mar} } @article{barletta_berkman_moody_el-masry_emara_reed_bedair_2007, title={Development of green, yellow, and amber light emitting diodes using InGaN multiple quantum well structures}, volume={90}, ISSN={["0003-6951"]}, DOI={10.1063/1.2721133}, abstractNote={The authors present optical and electrical data for long wavelength (573–601nm) InGaN∕GaN multiple quantum well light emitting diodes (LEDs) grown by metal organic chemical vapor deposition. These results are achieved by optimizing the active layer growth temperature and the quantum well width. Also, the p-GaN is grown at low temperature to avoid the disintegration of the InGaN quantum wells with high InN content. A redshift is observed for both the green and yellow LEDs upon decreasing the injection current at low current regime. In the case of the yellow LED, this shift is enough to push emission into the amber (601nm).}, number={15}, journal={APPLIED PHYSICS LETTERS}, author={Barletta, Philip T. and Berkman, E. Acar and Moody, Baxter F. and El-Masry, Nadia A. and Emara, Ahmed M. and Reed, Mason J. and Bedair, S. M.}, year={2007}, month={Apr} } @article{mahros_luen_emara_bedair_berkman_el-masry_zavada_2007, title={Magnetic and magnetotransport properties of (AlGaN/GaN): Mg/(GaMnN) heterostructures at room temperature}, volume={90}, ISSN={["0003-6951"]}, DOI={10.1063/1.2749717}, abstractNote={Dilute magnetic semiconductor films (GaMnN) are highly resistive, making transport measurements difficult to achieve. However, when GaMnN films are sandwiched between p-type doped (AlGaN∕GaN) strained-layer superlattices, holes from the superlattice interact with the Mn3+∕2+ ions and transport measurements were realized. The authors have found also that the ferromagnetic properties of GaMnN critically depend on the level of p-type doping in the superlattice. They report anomalous Hall effect measurements in this (AlGaN∕GaN):Mg∕(GaMnN) multilayered structure. The current results also demonstrate the role of carriers, especially holes, in mediating the ferromagnetic properties of GaMnN dilute magnetic semiconductor films.}, number={25}, journal={APPLIED PHYSICS LETTERS}, author={Mahros, Amr M. and Luen, M. O. and Emara, A. and Bedair, S. M. and Berkman, E. A. and El-Masry, N. A. and Zavada, J. M.}, year={2007}, month={Jun} } @inproceedings{emara_berkman_zavada_el-masry_bedair, title={Strain relaxation in InxGa1-xN/GaN quantum well structures}, volume={8}, number={7-8}, booktitle={Physica status solidi c: current topics in solid state physics, vol 8, no 7-8}, author={Emara, A. M. and Berkman, E. A. and Zavada, J. and El-Masry, N. A. and Bedair, S. M.} }