Fig. 1. Cross-section of MOVPE stack containing three BSF/InGaAsP/BSF DHs.

Fig. 2. Cross-section of the InGaAsP/InGaAs double-junction solar cell structure.

Fig. 3. Element profiles (a) and PL decay curves (b) for InP-barrier and InAlAs-barrier DH1s.

Fig. 4. Overall SIMS results of (a) InP-barrier DH stack and (b) InAlAs-barrier DH stack.

Fig. 5. PL decay curves of (a) InP-barrier DHs and (b) InAlAs-barrier DHs.

Fig. 6. Steady-state PL of (a) InP-barrier DHs and (b) InAlAs-barrier DHs. Weak peaks marked by asteroids in DH1 and DH2 are related to the spacers.

Fig. 7. (a) Light J-V and (b) spectra response curves for InGaAsP/InGaAs solar cells using InP and InAlAs BSF layers

Fig. 8. Light J-V for InGaAsP/InGaAs DJSC using 5-period InP/InAlAs SL BSF layer.