Reactive Sputtering of Magnesium Hydride Thin Films for Photovoltaic Applications

Abstract

Deposition of MgHx (MgH2 + Mg) thin films is performed using RF reactive sputtering in argon-hydrogen plasma. Films are characterized using x-ray diffraction (XRD), scanning electron microscopy, optical and resistivity measurements. Formation of crystalline MgH2 is confirmed by XRD, but the formation of some metallic Mg in the films could not be avoided. Increased H/Mg ratio by deposition at high hydrogen flow or high total pressure gives films that oxidize within days or weeks. Deposition at elevated substrate temperature results in improved crystallinity and stability. Initial studies of MgHx for silicon surface passivation are presented.

Interface engineering of Cu(In,Ga)Se2and atomic layer deposited Zn(O,S) heterojunctions

“…The latter sulfurized S-free CIGSe absorbers in H 2 S before the buffer deposition, which emphasizes the importance of S in interface formation found in the present study. Platzer-Björkman et al obtained 16% conversion efficiency of solar cells back in 2003 15) and 16.4% later in 2006. 17…”

“…One promising alternative buffer layer material for achieving a high conversion efficiency of the respective solar cells and modules is Zn(O,S), which may be deposited by, e.g., CBD, 2,5,6) magnetron sputtering, [7][8][9][10][11][12][13][14] or atomic layer deposition (ALD). [15][16][17][18][19][20] CBD of Zn(O,S) buffer layers is already applied in highly efficient solar cells 2,6) but this technologyin comparison with sputtering and ALDoffers limited options for the deliberate adjustment of [S]= ([S]+[O]) (SSO) ratios. Studies on this topic using sputtering and ALD methods have shown that there seems to be an optimal range of the SSO ratio, at least for the particular sample under investigation.…”