Appl. Phys. Lett. 107, 141109 (2015)

Credit: © AIP PUBLISHING LLC

For emitters inside cavities, control over the wavelength of the emitter and the cavity modes is important for bringing both into resonance with each other and exploiting effects such as Purcell enhancement. Maurangelo Petruzzella and co-workers from The Netherlands, Denmark and the UK have now reported a method for accomplishing this in a solid-state system. Their semiconductor device supports independent electrical control of both the emitter and the cavity. The device consists of low-density InAs quantum dots embedded in the upper membrane of two parallel mechanically reconfigurable photonic crystal membranes. A p–i–n diode realized across the top membrane governs the energy of the quantum dots and thus their emission wavelength via the quantum-confined Stark effect. A second p–i–n diode connected to the bottom membrane controls the cavity resonance through capacitive force-induced displacement of the membrane. By combining Stark tuning of quantum dots with nanoelectromechanical actuation of the cavity, reversible wavelength tuning of the emitter over 7.5 nm and a mode shift of the cavity over 8.5 nm are achieved. As a result, a single exciton transition is brought into resonance with the cavity mode allowing a tenfold enhancement of its spontaneous emission.