Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 65: Nitrides: AlGaN

HL 65.1: Vortrag

Mittwoch, 16. März 2011, 17:00–17:15, POT 51

Si Doping Studies in AlGaN — •Kamran Forghani¹, Mohammadreza Gharavipour¹, Ferdinand Scholz¹, Benjamin Neuschl², Tobias Meisch², Ingo Tischer², Klaus Thonke², Oliver Klein³, and Ute Kaiser³ — ¹Institute of Optoelectronics, Ulm University, 89069 Ulm, Germany — ²Institute of Quantum Matter, Ulm University, 89069 Ulm, Germany — ³Transmission Electron Microscopy Group, Ulm University, 89069 Ulm, Germany

Realization of n-type conductivity in AlGaN is essential for the growth of deep-UV LED devices. For MOVPE grown layers, we have investigated the relation between Si concentration and carrier concentration at different Al contents up to about 45%. For higher Al contents, the samples suffer from micro cracks as the doping concentration increases. The cracks could be suppressed by growing the Si-doped AlGaN layers on short period super lattice buffer structures. In order to determine the dopant ionization energy, we have performed temperature-dependent Hall measurements on the samples with different Al content, Si concentration, and crystal quality. Moreover, we performed TEM, XRD, and AFM to quantify threading dislocations behavior, crystal quality and surface properties, respectively. The photoluminescence from GaN quantum wells grown on these doped layers was used as a monitor to evaluate their influence on future UV-LED device performance.