[13p-A202-1~17] 13.9 Compound solar cells

▼ [13p-A202-11] Effect of Compressive Strain in Multiple Quantum Well Solar Cell

〇(P)WARAKORN YANWACHIRAKUL¹, TETSUYA NAKAMURA^1,2, MAUI HINO¹, HASSANET SODABANLU¹, KENTAROH WATANABE¹, YOSHIAKI NAKANO¹, MASAKAZU SUGIYAMA¹ (1.Univ. of Tokyo, 2.JAXA)

Keywords:compressive-strained multiple quantum well, III-V semiconductor

InGaAs/GaAs compressive-strained (CS) and InGaAs/GaAsP strain-balanced (SB) multiple quantum well (MQW) solar cells were fabricated and characterized to investigate the effect of strain to the performance of MQW solar cells. By changing the barrier material from GaAsP to GaAs, the interfacial defects would decrease owing to smaller lattice mismatch between the well and the barrier materials, but the accumulation of strain in an entire MQW would increase. In this work, the samples of 5, 10 and 20-period of CS MQW, 10-period of SB MQW, nip and np GaAs reference cells were grown by metal-organic chemical vapor-phase deposition (MOCVD). For nip GaAs reference cell, the MQW layer was substituted by i-GaAs, and, for np GaAs reference cell, the i-GaAs top, MQW and i-GaAs bottom were substituted by p-GaAs base layer. Our results show the open-circuit voltage (V_oc) of 10-period SB MQW cell is 0.85 V, which is close to the V_oc of nip GaAs reference cell. The V_oc of CS MQW cell significantly decreases with increasing the number of MQW. This decrease of V_oc is attributed to the accumulated strain in the CS MQW structure.