Charge control in quantum dots

Context of project
​Research on single quantum dots has delivered breakthrough studies taking advantage of these artificial atom-like systems. One of the main properties of single dots is the relatively good isolation of carriers from the surrounding environment. Nonetheless, such good isolation complicates the deterministic control of changes coming in and out of the dots. In particular, such charge control is essential for applications as single photon sources and robust spins control.    
    
Review on coherent optical control of spin states in semiconductor quantum dots ref:
[1] iopscience.iop.org/article/10.1088/0268-1242/25/10/103001/meta

Our work 
We demonstrate control by applied electric field of the charge states in single self-assembled InP quantum dots placed in GaInP Schottky structures grown by metalorganic vapor phase epitaxy. This has been enabled by growth optimization leading to suppression of formation of large dots uncontrollably accumulating charge. Using bias- and polarization-dependent micro-photoluminescence, we identify the exciton multiparticle states and carry out a systematic study of the neutral exciton state dipole moment and polarizability. This analysis allows for the characterization of the exciton wave-function properties at the single-dot level for this type of quantum dot. Photocurrent measurements allow further characterization of exciton properties by electrical means, opening new possibilities for resonant excitation studies for such systems. 

Read more:
​Charge control in InP/(Ga, In) P single quantum dots embedded in Schottky diodes
O.D.D. Couto Jr, J. Puebla, E.A. Chekhovich, I.J. Luxmoore, C.J. Elliott, N. Babazadeh, M.S. Skolnick, A.I. Tartakovskii, A.B. Krysa
Physical Review B 84 (12), 125301 (2011)
journals.aps.org/prb/abstract/10.1103/PhysRevB.84.125301
Personal contribution: Device fabrication, performed experiments and analyze data