Light emission and spin-polarised hole injection in InAs/GaAs quantum dot heter...

• Author(s): Baidus, N. V. ; Vasilevskiy, Mikhail ; Khazanova, S. V. ; Zvonkov, B. N. ; Meulen, H. P. van der ; Calleja, J. M. ; Vinã, L.
• Date: 2012
• Persistent ID: http://hdl.handle.net/1822/20898
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Optical properties of low-dimensional, mesoscopic, and nanoscale materials; Spin transport through interfaces
• Document Type: Article
• Language: English

Description

EPL draft We demonstrate the feasibility to obtain electroluminescence (EL), up to room temperature, from InGaAs self-assembled quantum dots (QDs) included in a forward-biased Schottky diode. Moreover, using a ferromagnet (FM) as the contact layer, sizable circular polarization of the EL emission in the presence of an external magnetic eld is obtained. A resonant behav- ior of the degree of circular polarization (P) as a function of applied voltage (V ), for a given value of magnetic eld, is observed. We explain our ndings using a model including tunneling of (spin-polarised) holes through the metal-semiconductor interface, transport in the near surface region of the heterostructure and out-of-equilibrium statistics of the injected carriers occupying the available states in the QD heterostructure. In particular, the resonant P(V ) dependence is related to the splitting of the qusi-Fermi level for two spin orientations in the FM.