[15p-A34-1~19] 13.10 Compound solar cells

▲ [15p-A34-17] Impact of dopant species on the properties of GaAs tunneling junctions for PV applications

〇(P)Hassanet Sodabanlu¹, Kentaroh Watanabe¹, Masakazu Sugiyama², Yoshiaki Nakano² (1.RCAST, U. of Tokyo, 2.U. of Tokyo)

Keywords:III-V solar cell, Tunneling junction

Several GaAs tunnelling junctions (TJ) grown by a planetary metalorgainc vapor phase epitaxy (MOVPE) reactor utilizing various dopants including Zn, C, S and Te were investigated. Highly C-doped GaAs was obtained by reducing the growth temperature and increasing the amount of H₂ carrier gas in order to prevent pre-decomposition of CBr₄ near the gas injection cone of MOVPE. With these strategies, C-doped GaAs with saturated free carrier concentration of approximately 10²⁰ cm^-3 could be realized. In case of n-doping, incorporation of Te atoms into GaAs was almost two orders larger than that of S atoms. The C-Te doped GaAs TJ exhibited the best ohmic-like tunneling behavior with a resistivity of 12.5 mW/cm², while the others had diode characteristics. The combination of C and Te has a good potential for low electrical loss TJs in MJSCs.