We propose to employ a selective formation method to embed an isolated self assembled quantum dot into a n-i-n junction to implement single electron transistors (SETs). The absorption and emission spectrum of SETs are theoretically studied by the Keldysh Green function method. The electronic levels and Coulomb interactions of electrons of InAs quantum dot (QD) are evaluated by an effective mass model. It is found that Coulomb interaction and level mixing in the many body open system lead to double peaks associated with the intraband transitions involving two lowest levels of the QD. We can electrically control the SETs as a single-photon source and double-photon source for 10 μm wavelength. The single photon source can be used in the application of quantum cryptograph, and the double-photon source can be utilized in the teleportation.