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HL: Fachverband Halbleiterphysik

HL 31: Poster I: Devices, Quantum Dots and Quantum Wires

HL 31.10: Poster

Dienstag, 23. März 2010, 18:30–20:30, Poster D1

Crack-free AlGaN-based UV LED on Si(111) substrate — •P. Saengkaew, A. Dadgar, J. Bläsing, H. Witte, M. Müller, K. M. Günther, T. Fey, B. Bastek, F. Bertram, M. v. Kurnatowski, M. Wieneke, T. Hempel, P. Veit, R. Clos, J. Christen, and A. Krost — FNW/IEP/AHE Otto-von-Guericke-Universität Magdeburg

To achieve low-cost UV LEDs on large-diameter substrates it is a very interesting approach to grow AlGaN on low-cost Si substrates. Here, AlGaN layers and AlGaN LED structures grown on Si(111) were additionally monitored by in-situ curvature measurements. They show that with the insertion of AlN-based SL buffer layers and LT-AlN interlayers, the AlGaN layers are under compressive stress during growth enabling to compensate tensile stress after cooling. To characterize the crystalline quality, HR-XRD measurements were performed. Cross-sectional TEM to investigate dislocation propagation and annihilation. N- and p- conductivities were achieved by Si and Mg doping of the layers, respectively. By C-V and Hall-effect measurements, the maximum free-electron concentration of 2.6E+18 cm-3 and free-hole concentration of 2.4E+17 cm-3 by using a structure of Mg-doped GaN/Al0.1Ga0.9N multilayers for the latter were determined. A GaN/Al0.1Ga0.9N MQW structure showed near UV-luminescence around 350-360 nm. The optical and electrical properties of AlGaN-based LED samples were further characterized by I-V, EL, PL and CL measurements. The I-V measurements show forward-diode characteristics with turn-on voltage about 2.6-3.1 V.