NOTICE: this is the author’s version of a work that was accepted for publication in J. Cryst. Growth. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in J. Cryst. Growth 230, 596 (2001) (http://dx.doi.org/10.1016/S0022-0248(01)01259-3)
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[en] The ac characteristics of GaN : Mg and undoped GaN layers, grown by MOVPE on sapphire substrates, are measured for a wide range of temperature and bias conditions, in order to investigate the effect of the magnesium-related level on the transport properties. Two peaks, whose height and position depend on the measurement temperature, are observed in the admittance curves (G/ω versus frequency) of the Mg-doped samples, whereas only one peak appears in undoped samples. The study of the frequency dependence of the impedance, with a model including the two metallic Au/GaN junctions, the GaN layer itself, shows that, besides the effect of the differential resistance of the layer which plays a role in both sample types, the presence of a Mg-related deep level contributes to the observed variations of the peaks in the admittance curves of the p-doped samples. Results of a theoretical steady-state and small-signal analysis based on numerical modelling of the Au/GaN/Au heterostructure complete our analysis.
Disciplines :
Physics
Author, co-author :
Nguyen, Ngoc Duy ; Université de Liège - ULiège > Département de physique > Physique des solides, interfaces et nanostructures
Germain, Marianne; Université de Liège - ULiège > Département de physique
Schmeits, Marcel; Université de Liège - ULiège > Département de Physique
Evrard, Roger ; Université de Liège - ULiège > Département de Physique
Schineller, Bernd; AIXTRON AG
Heuken, Michael; AIXTRON AG
Language :
English
Title :
Experimental and theoretical investigations of the electrical properties of undoped and magnesium-doped GaN layers