Large-area Hybrid Silicon Heterojunction Solar Cells with Ni/Cu Plated Front Contacts

Abstract

Ni/Cu plated front contacts are applied to large-area hybrid silicon heterojunction (SHJ) solar cells consisting of a diffused front surface field and intrinsic and boron doped a-Si:H(i/p+) layers forming the rear SHJ emitter. Nickel silicide front contacts are formed by excimer laser annealing (ELA) which unlike rapid thermal annealing (RTA) is shown to be compatible with a rear SHJ emitter. A top efficiency of 20.1% (externally confirmed at FhG-ISE CalLab), with jsc=39.0mA/cm2, Voc=675.1mV, and FF=76.5% is obtained on 15.6x15.6 cm2 n-type Cz-Si in a first trial and this without compromising solder tab adhesion results at the front side. Limitations arising from series resistance at the rear side and from recombination at the front side are discussed.