Electrical spin injection and transport in semiconductor nanowires: challenges, progress and perspectives

Abstract

Spintronic devices are of fundamental interest for their nonvolatility and great potential for low-power electronics applications. The implementation of those devices usually favors materials with long spin lifetime and spin diffusion length. Recent spin transport studies on semiconductor nanowires have shown much longer spin lifetimes and spin diffusion lengths than those reported in bulk/thin films. In this paper, we have reviewed recent progress in the electrical spin injection and transport in semiconductor nanowires and drawn a comparison with that in bulk/thin films. In particular, the challenges and methods of making high-quality ferromagnetic tunneling and Schottky contacts on semiconductor nanowires as well as thin films are discussed. Besides, commonly used methods for characterizing spin transport have been introduced, and their applicability in nanowire devices are discussed. Moreover, the effect of spin-orbit interaction strength and dimensionality on the spin relaxation and hence the spin lifetime are investigated. Finally, for further device applications, we have examined several proposals of spinFETs and provided a perspective of future studies on semiconductor spintronics.

Large spin accumulation and crystallographic dependence of spin transport in single crystal gallium nitride nanowires

“…In the first step, the surface oxide of the GaN NW was removed with a hydrofluoric acid dip and a 1.5 nm thick MgO tunnel barrier and 30 nm-thick CoFeB electrodes were subsequently deposited in a DC magnetron sputter system. The MgO layer is uniform and free of pinholes, ensuring high spin injection/detection efficiency8945. Next, a Ta/Ru (5/5 nm) bilayer was deposited as a cap to prevent surface oxidation of the CoFeB.…”

Optical and Magnetic Properties of Ni Doped ZnS Diluted Magnetic Semiconductors Synthesized by Hydrothermal Method

“…For ZnS nanocrystals semiconductor with direct band structure, = 1/2 and ( ℎ]) 2 gives the best linear fitting curve in the band edge region. The relationship between ( ℎ]) 2 and ℎ] is shown in Figure 5(b). The values of are obtained by extrapolating the straight portion of the curve on ℎ] axis at = 0.…”

“…Diluted magnetic semiconductors refer to a new type of semiconductor material with both spin and charge degrees of freedom that is formed by the substitution of transition metals and rare earth ions to a small fraction of nonmagnetic cations in nonmagnetic semiconductors [1,2]. DMS nanocrystals have attracted scientific community for new spintronic optoelectronic devices due to its novel properties and broad application prospect, such as fieldemission devices, spin field-effect transistors, spin polarized light emitting diode, optical isolator, and quantum computer [3][4][5][6][7][8].…”

Spin state switching of metal complexes by visible light or hard X-rays

“…1,2 In this context, coordination compounds presenting spin crossover (SCO) phenomena are currently considered to be potential materials of choice. These compounds are reversibly convertible between a low-spin (LS) state and a high-spin (HS) state by an external stimulus.…”