Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: Poster III

HL 36.38: Poster

Wednesday, February 27, 2008, 16:30–19:00, Poster D

Hall effect measurements on AlInN layers with high In-content and low Hall mobility — •Kay-Michael Günther, Hartmut Witte, Christoph Hums, Armin Dadgar, and Alois Krost — Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Magdeburg

At AlInN/GaN interfaces grown with strained AlInN on GaN and with Indium concentrations above 32 % a p-channel is expected. For such material, a precise characterization of the electrical and transport properties by Hall-effect measurements is fundamental. In the case of low mobility and/or high resistance such measurements are very difficult: the Hall voltage is about 100-1000 times smaller than the voltage drop without the magnetic field. The apparent Hall coefficient is not caused by a free carrier concentration but rather by dynamic persistent or storage processes due to inhomogeneities within the AlInN layers. However, even in the case of extremely noisy signals useful information, e.g. on the type of carriers can be extracted by comparing the average values of many Hall-effect measurements with and without a magnetic field. Furthermore, the noise can be reduced by lock-in measurements.