We report on incorrect carrier type identification achieved by Hall effect measurements performedon ZnO films grown by pulsed laser deposition on InP substrates and subsequently annealed for 1 hat 600 C in air. While Hall measurements, after post-growth annealing, reveal a change in theelectrical properties of the films, from n-type to p-type, both photocurrent-based and standard C Vmeasurements performed on the same samples show no change in the native n-type doping of theZnO films. A possible interpretation of the two results is reported. In particular, p-type conductivityobserved by Hall effect may be ascribed to a highly conductive thin layer formed during theannealing process at the ZnO/InP interface, which dominates the Hall effect measurements anddoes not influence the photo-electrochemical behavior of ZnO as well as the measured differentialcapacitance. The conflicting results here reported show that for this kind of samples, Hall effectmeasurement can be misleading with respect to the real nature of the analyzed material, insteadboth C V and photocurrent-based characterization techniques are more reliable and thereforecould be alternatively used when particularly ambiguous results are expected by Hall effectmeasurements.
|Numero di pagine||7|
|Rivista||Journal of Applied Physics|
|Stato di pubblicazione||Published - 2013|
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