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Temperature-Dependent Asymmetry of Anisotropic Magnetoresistance in Silicon p-n Junctions.

Yang DZ, Wang T, Sui WB, Si MS, Guo DW, Shi Z, Wang FC, Xue DS - Sci Rep (2015)

Bottom Line: More interestingly, in contrast with other materials, the lineshape of anisotropic magnetoresistance in silicon p-n junctions significantly depends on temperature.As temperature decreases from 293 K to 100 K, the width of peak shrinks from 90° to 70°.Therefore, the observed temperature-dependent asymmetry of magnetoresistance is proved to be a direct consequence of the spatial configuration evolution of space charge region with temperature.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Magnetism and Magnetic materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China.

ABSTRACT
We report a large but asymmetric magnetoresistance in silicon p-n junctions, which contrasts with the fact of magnetoresistance being symmetric in magnetic metals and semiconductors. With temperature decreasing from 293 K to 100 K, the magnetoresistance sharply increases from 50% to 150% under a magnetic field of 2 T. At the same time, an asymmetric magnetoresistance, which manifests itself as a magnetoresistance voltage offset with respect to the sign of magnetic field, occurs and linearly increases with magnetoresistance. More interestingly, in contrast with other materials, the lineshape of anisotropic magnetoresistance in silicon p-n junctions significantly depends on temperature. As temperature decreases from 293 K to 100 K, the width of peak shrinks from 90° to 70°. We ascribe these novel magnetoresistance to the asymmetric geometry of the space charge region in p-n junction induced by the magnetic field. In the vicinity of the space charge region the current paths are deflected, contributing the Hall field to the asymmetric magnetoresistance. Therefore, the observed temperature-dependent asymmetry of magnetoresistance is proved to be a direct consequence of the spatial configuration evolution of space charge region with temperature.

No MeSH data available.


The transport characteristics of the p-n junctions modulated by the magnetic field.(a) The p-n junction device structure and its measurement (b) Schematic illustration of the origin of the MR effect in p-n junctions due to the change of the space charge region tuned by magnetic field. Without the magnetic field a uniform distribution in space-charge region is formed, while under magnetic field a trapezoidal distribution of space charger region is formed due to the Lorentz force and the current trajectory are deflected toward the lower barriers. The corresponding I-V curves of the p-n junctions under the magnetic field H = 2 T with angle θ from 0° to 90° at 293 K (c) and 140 K (d), demonstrating the significant temperature-dependent anisotropic MR effect.
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f1: The transport characteristics of the p-n junctions modulated by the magnetic field.(a) The p-n junction device structure and its measurement (b) Schematic illustration of the origin of the MR effect in p-n junctions due to the change of the space charge region tuned by magnetic field. Without the magnetic field a uniform distribution in space-charge region is formed, while under magnetic field a trapezoidal distribution of space charger region is formed due to the Lorentz force and the current trajectory are deflected toward the lower barriers. The corresponding I-V curves of the p-n junctions under the magnetic field H = 2 T with angle θ from 0° to 90° at 293 K (c) and 140 K (d), demonstrating the significant temperature-dependent anisotropic MR effect.

Mentions: The schematic illustration of the p-n junction device structure as well as the measurement diagram is shown in Fig. 1a. The vertical geometry of Si(p+)/Si(n)/Si(n+) is chosen to form a wide space charge region. At room temperature the carrier densities of Si(p+), Si(n), and Si(n+) were 2.0 × 1014  cm−3, 1.0 × 1012 cm−3 and 1.0 × 1015  cm−3, respectively. The angular dependence of MR was measured by rotating the sample holder under a fixed magnetic field H = 2 T and a current I = 20 mA. The orientation of H was defined as θ, which is the angle between the H and z axes. During the whole measurement the magnetic field is rotated in the x–z plane. Here the MR ratio is defined as (R(H)−R(0))/R(0) × 100%.


Temperature-Dependent Asymmetry of Anisotropic Magnetoresistance in Silicon p-n Junctions.

Yang DZ, Wang T, Sui WB, Si MS, Guo DW, Shi Z, Wang FC, Xue DS - Sci Rep (2015)

The transport characteristics of the p-n junctions modulated by the magnetic field.(a) The p-n junction device structure and its measurement (b) Schematic illustration of the origin of the MR effect in p-n junctions due to the change of the space charge region tuned by magnetic field. Without the magnetic field a uniform distribution in space-charge region is formed, while under magnetic field a trapezoidal distribution of space charger region is formed due to the Lorentz force and the current trajectory are deflected toward the lower barriers. The corresponding I-V curves of the p-n junctions under the magnetic field H = 2 T with angle θ from 0° to 90° at 293 K (c) and 140 K (d), demonstrating the significant temperature-dependent anisotropic MR effect.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555100&req=5

f1: The transport characteristics of the p-n junctions modulated by the magnetic field.(a) The p-n junction device structure and its measurement (b) Schematic illustration of the origin of the MR effect in p-n junctions due to the change of the space charge region tuned by magnetic field. Without the magnetic field a uniform distribution in space-charge region is formed, while under magnetic field a trapezoidal distribution of space charger region is formed due to the Lorentz force and the current trajectory are deflected toward the lower barriers. The corresponding I-V curves of the p-n junctions under the magnetic field H = 2 T with angle θ from 0° to 90° at 293 K (c) and 140 K (d), demonstrating the significant temperature-dependent anisotropic MR effect.
Mentions: The schematic illustration of the p-n junction device structure as well as the measurement diagram is shown in Fig. 1a. The vertical geometry of Si(p+)/Si(n)/Si(n+) is chosen to form a wide space charge region. At room temperature the carrier densities of Si(p+), Si(n), and Si(n+) were 2.0 × 1014  cm−3, 1.0 × 1012 cm−3 and 1.0 × 1015  cm−3, respectively. The angular dependence of MR was measured by rotating the sample holder under a fixed magnetic field H = 2 T and a current I = 20 mA. The orientation of H was defined as θ, which is the angle between the H and z axes. During the whole measurement the magnetic field is rotated in the x–z plane. Here the MR ratio is defined as (R(H)−R(0))/R(0) × 100%.

Bottom Line: More interestingly, in contrast with other materials, the lineshape of anisotropic magnetoresistance in silicon p-n junctions significantly depends on temperature.As temperature decreases from 293 K to 100 K, the width of peak shrinks from 90° to 70°.Therefore, the observed temperature-dependent asymmetry of magnetoresistance is proved to be a direct consequence of the spatial configuration evolution of space charge region with temperature.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Magnetism and Magnetic materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China.

ABSTRACT
We report a large but asymmetric magnetoresistance in silicon p-n junctions, which contrasts with the fact of magnetoresistance being symmetric in magnetic metals and semiconductors. With temperature decreasing from 293 K to 100 K, the magnetoresistance sharply increases from 50% to 150% under a magnetic field of 2 T. At the same time, an asymmetric magnetoresistance, which manifests itself as a magnetoresistance voltage offset with respect to the sign of magnetic field, occurs and linearly increases with magnetoresistance. More interestingly, in contrast with other materials, the lineshape of anisotropic magnetoresistance in silicon p-n junctions significantly depends on temperature. As temperature decreases from 293 K to 100 K, the width of peak shrinks from 90° to 70°. We ascribe these novel magnetoresistance to the asymmetric geometry of the space charge region in p-n junction induced by the magnetic field. In the vicinity of the space charge region the current paths are deflected, contributing the Hall field to the asymmetric magnetoresistance. Therefore, the observed temperature-dependent asymmetry of magnetoresistance is proved to be a direct consequence of the spatial configuration evolution of space charge region with temperature.

No MeSH data available.