Spin-polarized electroluminescence and spin-dependent photocurrent in hybrid semiconductor/ferromagnetic heterostructures: An asymmetric problem

Renucci, Pierre; Truong, Viet Giang; Jaffrès, Henri; Lombez, Laurent; Binh, Pham Thanh; Amand, T.; George, Jean-Marie; Marie, X.

doi:10.1103/physrevb.82.195317

Cited by 27 publications

(28 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For this reason, in analogy with spin‐LEDs, these devices are usually referred as “spin‐photodiodes” (spin‐PDs). Direct FM/SC interfaces with Schottky barriers,8 complex structures involving insulating tunneling barriers9, 10 and p‐i‐n photodiodes with an embedded quantum well,11 have been investigated. However, all of the previous work has employed a III–V semiconductor as the optically active layer, and, up to now, there has been no clear demonstration of Ge‐based spin‐PDs that present a sizable spin filtering at room temperature.…”

mentioning

confidence: 99%

Ge‐Based Spin‐Photodiodes for Room‐Temperature Integrated Detection of Photon Helicity

et al. 2012

View full text Add to dashboard Cite

Spin-optoelectronics is a novel research area at the crossroads between the fundamental physics of quantum-mechanical spin, optoelectronics, and nanotechnology. [ 1 ] Spin-and light-polarization effects in nanostructures, possibly involving the confi nement of both charges and photons, are very appealing for the implementation of innovative optoelectronic systems. In particular, the coupling between the photon helicity and the spin angular momentum of electrons can be used for the magnetically controlled generation and detection of circularly polarized light, to be employed in systems exploiting the additional degree of freedom connected to the light polarization. [ 2 ] Multiple-statelogic and novel communication protocols can be implemented based on the capability of manipulating and detecting the different polarization states of light pulses (linear, circularly left and right) in integrated platforms without the use of external optical elements. In this framework, novel devices such as optical interconnects, optical switches, and modulators [ 3 , 4 ] can be realized with reconfi gurable functionality depending on the confi guration of the magnetic electrodes embedded in the emitters and detectors of the polarized light.Providing that the integrated emitters and detectors of polarized light have enough sensitivity to operate on single photons, the information, ultimately carried out by the spin of electrons and photons, can be encoded in the confi ned spin state, manipulated at the nanoscale and redelivered in the form of polarized photons. Major future applications of such a novel approach comprise the areas of quantum computing and data-transmission cryptography based on the coherent interaction between qubits via photon-polarization effects. [ 5 ] During the last decade, there have been many attempts to implement the integrated electrical detection of light helicity. The spin voltaic effect in graded p-n junctions has been recently employed, [ 6 ] but most work has essentially used spin-LEDs operating in the reverse way. [ 7 ] In these pieces of work, the spin fi ltering of photogenerated carriers in a semiconductor (SC) during their motion towards a ferromagnetic (FM) electrode is exploited to convert the electron spin polarization into a modulation of the photocurrent. For this reason, in analogy with spin-LEDs, these devices are usually referred as "spin-photodiodes" (spin-PDs). Direct FM/SC interfaces with Schottky barriers, [ 8 ] complex structures involving insulating tunneling barriers [ 9 , 10 ] and p-i-n photodiodes with an embedded quantum well, [ 11 ] have been investigated. However, all of the previous work has employed a III-V semiconductor as the optically active layer, and, up to now, there has been no clear demonstration of Ge-based spin-PDs that present a sizable spin fi ltering at room temperature.Although for many years GaAs has been the unquestioned reference material for semiconductor spintronics, recently considerable attention has been devoted to Ge. Spin manipulation, [ 12 ] electric...

show abstract

mentioning

confidence: 99%

Ge‐Based Spin‐Photodiodes for Room‐Temperature Integrated Detection of Photon Helicity

et al. 2012

View full text Add to dashboard Cite

show abstract

“…3 This explains the large amount of work on spintronics with hybrid metal/semiconductor heterostructures for the past ten years, once it was proposed to solve the problem of impedance mismatch 4 by the use of an interface resistance, typically a tunneling barrier. [5][6][7] Various experiments have been performed to detect by electrical (e.g., the electrical Hanle effect) or by optical means a spin-polarized current injected from a ferromagnetic reservoir into a III-V semiconductor through an Al 2 O 3 barrier, [8][9][10][11][12] through MgO, [12][13][14][15][16] and through GaO, 17 or into Si through Al 2 O 3 (Refs. [18][19][20][21][22] and SiO 2 (Refs.…”

Section: Introductionmentioning

confidence: 99%

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

et al. 2012

Self Cite

View full text Add to dashboard Cite

We have studied the perpendicular magnetic anisotropy of Co/Pt multilayers and the electron spin injection efficiency by optical spectroscopy from a [Co(0.6 nm)/Pt(1 nm)] 4 /Fe(0.3 nm)/MgO perpendicular tunnel spin injector grown on AlGaAs/GaAs semiconductor light-emitting diodes. We observe a 2.5% circular polarization at low temperature close to the magnetic remanence when the 0.3 nm Fe film of the ferromagnetic injector is sufficiently thin to maintain the magnetization out of plane. The acquired squared magnetization cycle is explained by the remaining interlayer exchange coupling existing between Fe and the (Co/Pt) multilayer through Pt or possible perpendicular magnetic anisotropy at the MgO/Fe interface. The corresponding spin polarization of the current is then estimated as 7%, measured by photoluminescence techniques, after the necessary uprenormalization, taking into account the electron spin-flip rate in the quantum well. In contrast, no circular polarization is observed when the thin Fe layer is removed and despite the rather high magnetic polarizability of the 5d 9 electronic open shell of Pt at the interface with MgO. This emphasizes the reduced size of tunneling branching of wave functions at the interface, of the order of the atomic plane unit.

show abstract

“…Though a very efficient electrical spin injection is demonstrated with a measured circular polarization of the electroluminescence up to 30% for an external field of 0.8 Tesla, very weak polarizations of the photocurrent are evidenced whatever the device is 43 . The maximum measured value of the photocurrent polarization obtained under resonant circularly polarized excitation of the quantum well excitons is about 3%.…”

Section: Resultsmentioning

confidence: 97%

Spin polarized electroluminescence and spin photocurrent in hybrid semiconductor/ferromagnetic heterostructures: an asymmetric problem

Renucci

Zhang

et al. 2011

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

The photocurrent obtained under polarized optical excitation and the polarized electroluminescence recorded under forward electric bias have been measured in the same hybrid Semiconductor/Ferromagnetic metal structures (Spin-Light Emitting Diode). Systematic investigations have been performed on devices with different ferromagnetic spin injectors, consisting e.g. of MgO tunnel barriers with a CoFeB ferromagnetic layer. Though a very efficient electrical spin injection is demonstrated, very weak polarization of the photocurrent is evidenced: the photocurrent polarization measured under continuous resonant circularly polarized excitation of the quantum well excitons is below 3%. This demonstrates that the investigated devices do not act as efficient spin filters for the electrons flowing from the semiconductor part to the ferromagnetic part of these structures though these systems are very efficient spin aligners for electrical spin injection. We interpret the weak measured photocurrent polarization of the as a consequence of the Zeeman splitting of the quantum well excitons which yields different absorption coefficients for the polarized excitation laser with different helicities. This leads to different intensities of photocurrent collected for the two different circularly polarized excitations. This interpretation is confirmed by an experiment exhibiting the same results for photocurrent measured on a device with a non ferromagnetic electrical contact.

show abstract

Spin-polarized electroluminescence and spin-dependent photocurrent in hybrid semiconductor/ferromagnetic heterostructures: An asymmetric problem

Cited by 27 publications

References 42 publications

Ge‐Based Spin‐Photodiodes for Room‐Temperature Integrated Detection of Photon Helicity

Ge‐Based Spin‐Photodiodes for Room‐Temperature Integrated Detection of Photon Helicity

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

Spin polarized electroluminescence and spin photocurrent in hybrid semiconductor/ferromagnetic heterostructures: an asymmetric problem

Contact Info

Product

Resources

About