p-Type a-Si:H/ZnO:Al and µc-Si:H/ZnO:Al thin-film solar cell structures—A comparative hard X-ray photoelectron spectroscopy study

The chemical and electronic properties of a-Si:H(B)/ZnO:Al and µc-Si:H(B)/ZnO:Al thin-film solar cell structures are studied by hard X-ray photoelectron spectroscopy (HAXPES). Using a combination of different X-ray excitation energies and deliberate sample design, we were able to select the probed volume, i.e., the silicon capping layer only or the silicon and zinc oxide layer (including the buried interface). For the a-Si:H(B) material, we find a higher deposition rate and a smaller value for the modified Auger parameter than for µc-Si:H(B). In addition, we find indications of a pronounced band bending limited to the very surface of the a-Si:H(B) and the µc-Si:H(B) layers, which is more distinct in the latter case.

[1]  G. Moretti.  Auger parameter and Wagner plot in the characterization of chemical states by X-ray photoelectron spectroscopy: a review , 1998 .

[2]  H. Okamoto,et al.  Hydrogenated amorphous silicon carbide as a window material for high efficiency a-Si solar cells , 1982 .

[3]  B. Rech,et al.  Hard x-ray photoelectron spectroscopy study of the buried Si/ZnO thin-film solar cell interface: Direct evidence for the formation of Si–O at the expense of Zn-O bonds , 2011 .

[4]  F. Schäfers,et al.  The high kinetic energy photoelectron spectroscopy facility at BESSY progress and first results , 2009 .

[5]  Johannes Meier,et al.  High-Efficiency Amorphous Silicon Devices on LPCVD-ZnO TCO Prepared in Industrial KAI TM-M R&D Reactor , 2009 .

[6]  T. Eickhoff.  Photoemissionsuntersuchungen an vergrabenen Grenzschichten SiO2/Si, SiO2/SiC und Thiolen auf Gold mit 3,0-5,5 keV Röntgenstrahlung , 2002 .

[7]  Bernd Rech,et al.  Transparent Conductive Zinc Oxide , 2008 .

[8]  J. Schmitt,et al.  Glow discharge processing in the liquid crystal display industry , 2002 .

[9]  Alan Howling,et al.  A voltage uniformity study in large-area reactors for RF plasma deposition , 1997 .

[10]  Y. Matsushita,et al.  Present Status of the NIMS Contract Beamline BL15XU at SPring‐8 , 2010 .

[11]  Bernd Rech,et al.  The effect of front ZnO:Al surface texture and optical transparency on efficient light trapping in silicon thin-film solar cells , 2007 .

[12]  M. Gorgoi,et al.  KMC-1: a high resolution and high flux soft x-ray beamline at BESSY. , 2007, The Review of scientific instruments.

[13]  L. Johansson,et al.  Studies of oxidized hexagonal SiC surfaces and the SiC/SiO2 interface using photoemission and synchrotron radiation , 2004 .

[14]  J. Müller,et al.  Development of highly efficient thin film silicon solar cells on texture-etched zinc oxide-coated glass substrates , 2001 .

[15]  J. Couderc,et al.  Reactor modeling for radio frequency plasma deposition of SiNxHy: Comparison between two reactor designs , 1996 .

[16]  D. R. Penn,et al.  Calculations of electron inelastic mean free paths , 2005 .

[17]  C. Ballif,et al.  Window layer with p doped silicon oxide for high Voc thin-film silicon n-i-p solar cells , 2011 .

[18]  Impact of solid-phase crystallization of amorphous silicon on the chemical structure of the buried Si/ZnO thin film solar cell interface , 2010 .

[19]  C. Beneking,et al.  Solution of the ZnO/p contact problem in a-Si:H solar cells , 1994, Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC).