Simulation of silicon heterostructure solar cell featuring dopant-free carrier-selective molybdenum oxide and titanium oxide contacts

Dopant-free carrier-selective transition metal oxide (TMO) contacts offer unique electrical properties pertaining to the rectification of doping-related issues in silicon (cSi) solar cell. In this paper, cSi heterojunction solar cell featuring TMOs of molybdenum oxide (MoOx) and titanium oxide (TiOx) as hole- and electron-selective contacts, respectively, has been realized using Silvaco TCAD. The photovoltaic performance has been evaluated based on the electron affinity of TiOx, its thickness, interfacial charge density, band gap, and operating temperature. MoOx with an appropriate work function prompts band bending leading to Fermi level pinning at top interface. Insertion of TiOx with low electron affinity reduces the rear energy barrier against electrons from 0.86 eV to 0.15 eV. Minimum recombination has been observed for electron affinity values range of 3.6-4.2 eV. The rear interface defects (D-it) should be minimized to reduce the recombination and to facilitate transportation of electrons. The device numerically demonstrated V-oc of 723 mV, J(sc) 39.2 mA/cm(2), FF 79.8%, and eta of 22.64% with temperature coefficient of -0.08%/degrees C. These results validate the applicability of heterojunction design with fully-covered carrier-selective contacts that can be useful for industrial applications as it eliminates the need of doped layers with the associated capital-intensive and complicated fabrication processes. (C) 2019 Elsevier Ltd. All rights reserved.