Improved two-step photon absorption current by Cl-doping in ZnTeO-based intermediate band solar cells with n-ZnS layer

We report the improved photocurrent induced by two-step photon absorption (TSPA) in the intermediate band solar cells (IBSCs) with a n-ZnS/ZnTe/ZnTeO/ZnTe/p-ZnTe structure using Cl-doped ZnTeO. In the IBSC with an undoped ZnTeO, the TSPA current is not observed at room temperature but it is significantly improved by using Cl-doped ZnTeO. Temperature and excitation intensity dependent photoluminescence (PL) spectra reveal the high activation energy of Cl-donor, and the observed activation temperature by PL measurements is consistent with the temperature where the TSPA current starts to increase. The temperature dependence of the open circuit voltage of the IBSC using Cl-doped ZnTeO also supports that the Cl doping in the ZnTeO layer introduces electrons into the intermediate band.

Automated summary

By doping Cl-doped ZnTeO, the photocurrent induced by two-step photon absorption in intermediate band solar cells is significantly improved. The high activation energy of Cl donor increases the activation temperature of TSPA current, while the introduction of electrons by Cl doping helps improve the open circuit voltage of IBSCs.