Various metal oxides are probed as extrinsic thin tunnel barriers in Semiconductor Insulator Semiconductor solar cells. Namely AlO, ZrO, YO, and LaO thin films are in between n-type ZnO:Al (AZO) and p-type Si substrates by means of Atomic Layer Deposition. Low reverse dark current-density as low as 3×10 A/cm, a fill factor up to 71.3%, and open-circuit voltage as high as 527 mV are obtained, achieving conversion efficiency of 8% for the rare earth oxide LaO. ZrO and notably AlO show drawbacks in performance suggesting an adverse reactivity with AZO as also indicated by X-ray Photoelectron Spectroscopy.

This work introduces a new software package "Sesame" for the numerical computation of classical semiconductor equations. It supports 1 and 2-dimensional systems and provides tools to easily implement extended defects such as grain boundaries or sample surfaces. Sesame is designed to facilitate fast exploration of the system parameter space and to visualize local charge transport properties. Sesame has been benchmarked against other software packages, and results for single crystal and polycrystalline CdS-CdTe heterojunctions are presented. Sesame is distributed as a Python package or as a standalone GUI application, and is available at https://pages.nist.gov/sesame/.