Light emitting single electron transistors
  The dynamic properties of light-emitting single-electron transistors (LESETs) made from quantum dots are theoretically studied by using nonequilibrium Green's function method. Holes residing at QD created by small ac signals added in the base electrode of valence band lead to the exciton assisted tunnelling level for the electron tunnelling from emitter to collector, it is therefore such small signals can be amplified. LESETs can be employed as efficient single-photon detectors. 
David M.-T. Kuo and Yia-chung Chang