[15a-P11-1~13] 15.3 III-V-group epitaxial crystals, Fundamentals of epitaxy

[15a-P11-8] Fabrication of InGaP solar cells grown on GaAs vicinal substrates by MBE

〇(M1)Yuki Nagato^1,2, Ryuji Oshima², Takeyoshi Sugaya², Yoshinobu Okano¹ (1.TCU, 2.AIST)

Keywords:MBE, InGaP, vicinal substrates

We studied the role of the substrate miscut on the properties of lattice-matched InGaP solar cells, which were grown on GaAs(001) by solid source molecular beam epitaxy. The bandgaps (Eg) of alloys grown on the substrates miscut toward (111)A were found to be wider than those of alloys grown on the exact substrate. A larger Eg leads to an enhanced open-circuit voltage (VOC). Conversely, Eg became narrower with an increasing the miscut angle for alloys grown on substrates miscut toward (111)B. Furthermore, both WOC (= Eg/q -VOC) and the fill factor parameter were improved from 0.59 V and 79.1% respectively for the cell grown on the exact substrate to 0.58 V and 86.1% for the cell grown on the substrate miscut 2° toward (111)B. This improvement is possibly due to the enhancement of single variant atomic ordering.