Capacitance-voltage characteristics of InAs dots: a simple model

Observation of the negative differential capacitance in Schottky diodes with InAs quantum dots near room temperature

“…The method for calculating the capacitance dependence was proposed to compare with the experimental results. [7][8][9] Particularly, in the work of Chiquito et al, 9 a negative differential capacitance ͑NDC͒ characteristic was observed at low temperatures and a model was provided to explain the results. However, in the consideration of practical application, such as quantum dot memory devices, the operation temperature has to be much higher.…”

“…That is, the n dot in formula ͑4͒ is nearly zero and thereby the ͑x͒ would tend to be classical. 8,9 When the applied reverse voltage decreases, the Fermi level E f approaches to the first energy level E dot1 and it leads to filling ground energy states with electrons. As a result, n dot1 increases as follows:…”

“…Because the capture/escape time for the second states ͑E dot2 ͒ in QDs could be much shorter, some of the electrons in the second states can catch up with the chargingdischarging process of the testing signal V . So, to take this effect into account we have to include an additional capacitance C dot2 : 8,9 C dot 2 = e dn dot 2…”

Investigation of electrically active defects in InGaAs quantum wire intermediate-band solar cells using deep-level transient spectroscopy technique

“…The distinct behaviours of the capacitance in QWR undoped devices can be related to a two-dimensional electron gas (2DEG) formation as a result of electron localisation in the InGaAs wetting layer (WL). Chiquito et al [27] observed a plateau-like dependence in their C-V measurements at the bias range 0.5 to 1.5 V in an InAs/ GaAs self-assembled QD system. They related this behaviour to the formation of 2DEG at the (GaAs) 4 /(AlAs) 11 /GaAs top interface rather than at the WL because their PL and Raman scattering measurements proved that there was no contribution of the WL.…”