Laser processes for future solar cells

The photovoltaic (PV) industry requires higher efficiencies at lower manufacturing costs to become competitive with other power generation techniques. There are several approaches to increase the efficiency of solar cells. For example enhancements of the way photons are absorbed and how they generate charge carriers with low losses. Today, the so called first generation of photovoltaic devices based on crystalline silicon wafers are produced on a multi-GW-level. However, in most production lines there is only one laser process used to electrically isolate front and rear side of the cell. Lasers are predestined to generate local structures which will be required to manufacture high efficient solar cells. As an example we will show results on the interaction of ultra short laser pulses with dielectric films on silicon. Second generation photovoltaic modules are based on thin films. These modules are monolithically interconnected by laser scribing of the films. Tools for amorphous silicon are well established, while there are a lot of challenges to scribe CIGS layers. Within this paper we will show new results on the temporal evolution of a laser induced "lift-off" process to scribe the molybdenum back electrode.

[1]  Bernd Spangenberg,et al.  Effect of laser annealing on crystallinity of the Si layers in Si/SiO2 multiple quantum wells , 2007 .

[2]  F. Secco d' Aragona,et al.  Dislocation Etch for (100) Planes in Silicon , 1972 .

[3]  G. Heinrich,et al.  Influence of Pulse Duration and Surface Topography on Laser Ablation of Silicon Nitride Layers on Thin Emitters , 2011 .

[4]  C. Hellwig,et al.  Laser ablation of thin molybdenum films on transparent substrates at low fluences , 2011 .

[5]  J. Liu.  Simple technique for measurements of pulsed Gaussian-beam spot sizes. , 1982, Optics letters.

[6]  E. Palik.  Handbook of Optical Constants of Solids , 1997 .

[7]  Jürgen Köhler,et al.  Laser Doped Selective Emitters Yield 0.5% Efficiency Gain , 2009 .

[8]  J. Palm,et al.  Towards Module Efficiencies of 16% with an Improved CIGSSe Device Design , 2011 .

[9]  Zhenhua Zhang,et al.  Selective removal of dielectric layers using picosecond UV pulses , 2009, LASE.

[10]  A. Letsch,et al.  Selective Laser Ablation of Thin Dielectrics on Solar Cells , 2011 .

[11]  M. Green.  Third generation photovoltaics : advanced solar energy conversion , 2006 .

[12]  R. Sinton,et al.  Contactless determination of current–voltage characteristics and minority‐carrier lifetimes in semiconductors from quasi‐steady‐state photoconductance data , 1996 .

[13]  Matthias Domke,et al.  Pump-Probe Investigations on the Laser Ablation of CIS Thin Film Solar Cells , 2011 .

[14]  Jan Benick,et al.  Industrially Feasible Rear Passivation and Contacting Scheme for High-Efficiency n-Type Solar Cells Yielding a $V_{\rm oc}$ of 700 mV , 2010, IEEE Transactions on Electron Devices.

[15]  G. Seifert,et al.  Selective ablation of thin SiO2 layers on silicon substrates by femto- and picosecond laser pulses , 2011 .

[16]  P. Engelhart,et al.  Laser Ablation of Passivating SINx Layers for Locally Contacting Emitters of High-Efficiency Solar Cells , 2006, 2006 IEEE 4th World Conference on Photovoltaic Energy Conference.

[17]  M. Green,et al.  22.8% efficient silicon solar cell , 1989 .

[18]  Stéphane Larouche,et al.  OpenFilters: open-source software for the design, optimization, and synthesis of optical filters. , 2008, Applied optics.