Abstract
Heterostructure films of the form n-Si/Si(tSi)/Fe(800 Å) were prepared by DC magnetron sputtering. In these films, the Si and Fe (800 Å) films were deposited onto n-Si(100) substrates. Substrates with different doping concentration ND were used. The thickness tSi of the interleaved Si layer is varied. For tSi = 0, the heterostructures form n-Si/Fe Schottky junctions. Structural studies on the samples as performed through XRD indicate the polycrystalline nature of the films. The magnetization data showed that the samples have in-plane easy axis of magnetization. The coercivity of the samples is of the order of 90 Oe. The I-V measurements on the samples showed nonlinear behavior. The diode ideality factor η = 2.6 is observed for the junction with ND = 1018 cm-3. The leakage current I0 increases with the increase of ND. Magnetic field has less effect on the electrical properties of the junctions. A positive magnetoresistance in the range 1 – 10 % was observed for the Si/Fe Schottky junctions in the presence of magnetic field of strength 2 T. The origin of the MR is analyzed using a model where the ratio of the currents across the junctions with and without the applied magnetic field, IH=2T/IH=0 is studied as a function of the bias voltage Vbias. The ratio IH=2T/IH=0 shows a decreasing trend with the Vbias, suggesting that the contribution to the MR in our n-Si/Fe Schottky junctions due to the spin dependent scattering is very less as compared to that due to the suppression of the impact ionization process.
Highlights
The metal and semiconductor interface has attracted a lot of attention because of its possible applications in the field of integrated electrical circuits.[1,2,3] Introduction of a magnetic species in the metal semiconductor interface opens up new avenues of research in the field of semiconductor technology
Recent studies on the hybrid structures consisting of ferromagnetic metal and semiconductor have shown interesting electrical properties and brought dramatic change in their magnetotransport properties, viz. an anomalous large positive magnetoresistace (PMR) have been reported in the case of magnetite based heterojunctions,[4,5,6,7,8,9] semiconductor-granular film heterostructures with Co based nanoparticles,[10] gold/semi-insulating-GaAs schottky interface,[11] ZnO based heterojunction,[12] etc
The structural properties of the samples were studied through X-ray diffraction (XRD)
Summary
Structure with Fe electrodes separated by a micron gap in a magnetic field of 90 kOe and bias current 1 μA. The PMR in the sample was sensitive to bias current and applied magnetic field They observed a cross over from positive to negative magnetoresistance with the decrease of temperature for the same sample. Volkov et al.[23] have reported abrupt changes of about 106 in the dc resistance and impedance value of Mn/SiO2/p-Si Schottky diode structures at low temperature (20 K) with an increase of magnetic field to 200 mT. They attributed these anomalies in the magnetoresistance to the magnetic field dependent suppression of impact ionization process. The reason for introducing the interleaved Si layer at the interface is to modify the interface which could bring a significant change in the magnetotransport and semiconducting properties of the heterostructures
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
