Rapid Thermal Processing of High Efficiency N-Type Silicon Solar Cells with Al Back Junction

Abstract

In this paper we report on the design, fabrication and modeling of 49 cm 2 , 200-mm thick, 1-5 W-cm, n-and ptype <111> and <100> screen-printed silicon solar cells. A simple process involving RTP front surface phosphorus diffusion, low frequency PECVD silicon nitride deposition, screen-printing of Al metal and Ag front grid followed by co-firing of front and back contacts produced cell efficiencies of 15.4% on n-type <111> Si, 15.1% on n-type <100> Si, 15.8% on p-type <111> Si and 16.1% on p-type <100> Si. Open circuit voltage was comparable for n and p type cells and was also independent of wafer orientation. High fill factor values (0.771-0.783) for all the devices ruled out appreciable shunting which has been a problem for the development of co-fired n-type <100> silicon solar cells with Al back junction. Model calculations were performed using PC1D to support the experimental results and provide guidelines for achieving >17% n-type silicon solar cells by rapid firing of Al back junction.

Quality improvement of screen-printed Al emitter by using SiO2 interfacial layer for industrial n-type silicon solar cells

“…The measured IQE data is matched well to the IQE calculated from the PC1D simulation, resulting a S r of 8000 cm/s. Comparing with the typical S r value of 10 6 cm/s found in literatures for industrial back junction solar cells with full area screen-printed Al rear surface, this is a small value, revealing good rear surface condition of our cells Ebong et al (2006).…”

A Highly Selective and Self‐Powered Gas Sensor Via Organic Surface Functionalization of p‐Si/n‐ZnO Diodes

“…In fact, simulations (see Figure S4.a) predict Voc,theor,leakage = 68 mV/diode considering a shunt resistances of around 30 cm 2 to account for these effects (to be compared with values around 1 kcm 2 for a commercial solar cell ). [19] Furthermore, the band diagram shows that the back contact is not ohmic, as the ZnO bands bend 0.59 eV at the ZnO/Au interface. This limits the forward current of the p-Si/n-ZnO structure but will not substantially affect the Voc, as no current is flowing under open circuit conditions.…”

“…The DFT calculations thus show that the electronic structure of the SAM-NO2 system indeed depends on the specific choice of the SAM and is strongly altered by the NO2 adsorption (shift of the HOMO and LUMO energies). Moreover, the relatively low position of the thiole-NO2 LUMO (high electron affinity (EA) of the system) and the relatively high position of the amine-NO2 HOMO (low ionization potential (IP) of the system) indicate a rather electron acceptor character for the thiole-NO2 system and a rather electron donor character for the amine-NO2 system [19,20] . This is consistent with the experimentally observed reversed signals of Voc of the thiole and amine functionalized NWs.…”