Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 11: Focused Session: Semi- and nonpolar group III nitrides I

HL 11.5: Talk

Tuesday, March 24, 2009, 12:00–12:15, HSZ 01

Thermal trap emissions associated with stacking faults in undoped non c-plane GaN — •Kay-Michael Günther, Hartmut Witte, Matthias Wieneke, Jürgen Bläsing, Armin Dadgar, and Alois Krost — Otto-von-Guericke-Universität Magdeburg

Recently, GaN-based materials are used in optoelectronic and microelectronic devices like LEDs, vertical cavity surface emitting laser or high electron mobility transistors. In some applications strong piezoelectric fields in c-plane GaN are undesired evoking for instance the quantum confined stark effect (QCSE). In this case the reduced polarization of non c-plane GaN layers is useful for better radiative efficiency. Unfortunately, due to its anisotropic nature the growth of semipolar GaN produces much more stacking faults than in c-axis oriented GaN. The basal and prismatic plane stacking faults act as deep defects which are well known from photoluminescence measurements. However, little is known on their thermal emission and trapping behavior. Therefore, we have characterized deep defects of a series of high resistance and undoped semipolar GaN samples grown by MOVPE on sapphire substrates by comparison of defect-related transitions in photoluminescence, thermal emissions in photocurrent spectroscopy and in thermally stimulated currents (TSC). These results are compared to measurements on polar c-plane GaN samples and the correlation between the stacking faults and thermal trap emissions is discussed.