Si-Doped InAs/GaAs Quantum Dot Solar Cell with Alas Cap Layers

Abstract

In this work, the effect of Si doping on InAs/GaAs quantum dot solar cells with AlAs cap layers is studied. The AlAs cap layers suppress the formation of the wetting layer during quantum dot growth. This helps achieve quantum dot state filling, which is one of the requirements for strong sub-bandgap photon absorption in the quantum dot intermediate band solar cell, at lower Si doping density. Furthermore, the passivation of defect states in the quantum dots with moderate Si doping is demonstrated, which leads to an enhancement of the carrier lifetime in the quantum dots, and hence the open-circuit voltage.

InAs/GaAs quantum dot solar cells with quantum dots in the base region

“…As a result, a number of efforts have been devoted to preventing the substantial voltage decrease in QDSCs. For example, intentional doping in QDs have been used to passivate the defect states or to form charge dots to suppress recombination [11]. Moreover, intentional n-type doping in QD, which exhibit negatively charged dots, can enhance the short-circuit current significantly without the deterioration of voltage [12].…”

Open circuit voltage recovery in quantum dot solar cells: a numerical study on the impact of wetting layer and doping

“…Thus, reduction of the WL somewhat relaxes the amount of doping level required for attaining large recovery. As a matter of fact, high density doping could even deteriorate the material quality inducing further non‐radiative recombination centres [6, 12]. Moreover, doping obviously causes some penalty in the achievable QD photogeneration.…”

Type-II InAs/GaAsSb Quantum Dot Solar Cells With GaAs Interlayer

“…This can be assigned to a high density of strain-induced dislocations that reduce minority carrier lifetime and diffusion length. Postgrowth rapid thermal annealing to remove the point defects, or introducing Si doping to the QDs can potentially recover the V OC [26]- [28]. The EQE spectra in Fig.…”