Figure 1 | NPG Asia Materials

Figure 1

From: Valley light-emitting transistor

Figure 1

(a) Circularly polarized electroluminescence from a p–i–n junction electrostatically formed in two-dimensional WSe2 (provided by Iwasa and coworkers4). (b) The momentum-conserving interband transitions in valley K (−K) couple to right- (left-) handed circularly polarized light only. Valley polarization of carriers can lead to circularly polarized luminescence. (c) In the absence of valley polarization, circularly polarized luminescence is possible in a large electric field, where the overlap between the electron and hole pockets becomes different in the two valleys due to the valley-dependent dispersions.

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