Thermal shift of the resonance between an electron gas and quantum dots: what is the origin?

摘要: The operation of quantum dots (QDs) at highest possible temperatures is desirable for many applications. Capacitance–voltage spectroscopy (C(V)-spectroscopy) measurements are an established instrument to analyse the electronic structure and energy levels self-assembled QDs. We perform C(V) in dark under influence non-resonant illumination, probing exciton states up on InAs QDs embedded a GaAs matrix ranging from 2.5 120 K. While small shift charging spectra resonance observed two spin degenerate electron s-state voltages with increasing temperature, huge visible electron–hole excitonic voltages. s2-peak moves slightly higher, s1-peak lower In contrast, surprisingly charged much upon temperature. derive rate-model allowing attribute value different contributions these shifts. Resonant tunnelling, state degeneracy hole generation rate combination Fermi distribution function turn out be great importance effects. differences shifting behaviour connected equilibria schemes peaks--s-peaks arise when tunnelling-in- out-rates become equal, while peaks occur, hole-generation rates balanced.