Improvement of optical and electrical properties of Boron-doped ZnO films by ITO buffer layers for photovoltaic application

Boron-doped ZnO (BZO) films were deposited by low pressure chemical vapor deposition (LPCVD) on glass substrates with tin-doped indium oxide (ITO) buffer layers varying from 0 to 100 nm in thickness. The effects of ITO thickness on the structural, optical and electrical properties of BZO/ITO stacks were investigated. The sheet resistances of BZO/ITO stacks were decreased with increasing of ITO thickness while haze factors for BZO/ITO stacks were saturated at an ITO thickness of 50 nm. X-ray diffraction spectra indicate that ITO (2 2 2) can promote the preferred orientation of BZO films changing from 〈1 1 0〉 to 〈1 0 0〉. The grain size of the BZO films with ITO buffer layers was larger than that of those without ITO buffer layers. The simulated short circuit current of the silicon thin film solar cell when using BZO/ITO stacks as the TCO layers can be increased by a factor of 1.06 at an ITO thickness of 100 nm.