[11p-N204-1~13] 13.9 Compound solar cells

▲ [11p-N204-12] Growth of Zn-Ge-O Thin Film as a Transparent Conductive Oxide With a Low Electron Affinity

〇(D)Dwinanri Egyna¹, Ryoma Yomeda², Kosuke Beppu², Takahiro Wada², Yamada Akira¹ (1.Tokyo Tech, 2.Ryukoku Univ.)

Keywords:window layer, transparent conductive oxide, CIGS soalr cell

An alternative material for a wide band gap Cu(In,Ga)(Se,Se)₂(CIGSSe₂) solar cell’s transparent conductive oxide (TCO) layer was investigated in this work. In our previous work, we determined through a numerical calculation that a low electron affinity n-type material is preferred for wide bandgap CIGSSe₂ solar cell application due to the band alignment requirements. Following that, we presented in the current work that the addition of Ge element into ZnO to form Zn-Ge-O thin film resulted in a lowering of the electron affinity through a band gap widening. The band gap engineering was performed through the Ge-content adjustment, which was controlled through the flow rate of Ge-source in the metal-oxide chemical vapour deposition (MOCVD) system. Thus, in this work, we have demonstrated the potential of the electron affinity control to achieve the ideal band alignment condition between the TCO and the absorber layer.