A semiconductor structure consisting of two coupled quantum wells embeddedinto the intrinsic region of a {\it p-i-n} junction is proposed to beimplemented as an intermediate band solar cell with ratchet state. Thelocalized conduction subband of the right-hand side quantum well is thought asthe intermediated band, while the excited conduction subband of the right-handside quantum well, coupled to right-rand side one, is thought to acts as theratchet state. The photo-excited electron in the intermediate band can tunnelout the thin barrier separating the wells and accumulate into ratchet subband.This might raise the electron probability of being hit by a second photon andexiting out to the continuum, increasing solar cell current. Is presented atemporal rate model for describing the charge transport properties of the cell.Calculations are carried out by solving the time-dependent Schr\"odingerequation applying the time evolution operator within a pertinent choice of thenon-commuting kinetic and potential operators. The efficiency in the generationof current is analyzed directly by studying the occupation of the subbandswells in the p-i-n junction, taking into account the injection and drainingdynamic provided by the electrical contacts connected to the cell. As a result,the efficiency in the generation of current was found to be directly correlatedto the relationship between optical generation and recombination ratesregarding to the scattering to the ratchet state rate. This suggests that agood coupling between the intermediate band and the additional band is a keypoint to be analyzed when developing an efficient solar cell.
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