Exciton Spin Injection in CdTe/Cd1-xMnxTe Double Quantum Wells

Abstract

Spin injection processes of excitons were studied by time-resolved photoluminescence in double quantum wells consisting of Cd 0.95 Mn 0.05 Te and CdTe layers. Selective excitation of the magnetic and non-magnetic wells confirms the dominant spin injection process from the magnetic well to the non-magnetic well. The exciton spin injection from the magnetic quantum well of Cd 0.95 Mn 0.05 Te arises with an injection time of 10 ps and induces a transient spin polarization with the degree of 0.20 in the non-magnetic well of CdTe. The exciton spin relaxation time in the CdTe well was found to be sufficiently longer than the exciton lifetime of 38 ps.

The origin of ferromagnetism in57Fe ion-implanted semiconducting 6H-polytype silicon carbide

“…They are promising candidates for efficient spin injection into semiconducting materials in order to fabricate spin-FETs (field effect transistors) and related devices [2]. For example, attempts at electrical and optical spin injection have been made involving GaMnAs, GaMnN, ZnMnSe and CdMnTe [3][4][5][6][7][8][9]. The most striking advantage of these materials, in favour of ferromagnetic metal contacts, is the absence of the resistivity mismatch problem [10] which has to be overcome in the case of metal contacts either by tunnelling barriers or highly doped Schottky barriers [11][12][13][14][15][16][17][18][19].…”

Optical and Structural Properties of Zn–Cd–Mn–Se Double Quantum Well Systems

“…Exciton tunneling in ZnCdMnSe/ZnSe/ ZnCdSe DQW is spin conserving, 14,15) and exciton spin relaxation time in NMS well is much larger than exciton life time. 16) The þ polarized excitons in the DMS well are expected to transfer to the NMS well via tunneling and relax to the lowest energy state and finally recombine with emission of þ photons. Excitons injected directly in the NMS well are polarized to up-spin ( À ) state due to negative Zeeman splitting in the NMS well, and the À polarized excitons relax to the lowest energy state and recombine with emission of À photons.…”