Comparison from Simulated Al_(0.3)Ga_(0.7)As/GaAs/Ge and Al_(0.3)Ga_(0.7)As/GaAs/Si/Ge to Experimental InGaP/GaAs/InGaNAsSb/Ge for Optimized Utilization of the Solar Spectrum

摘要

To make full use of the solar spectrum, the performances of Al_(0.3)Ga_(0.7)As/GaAs/Ge and Al_(0.3)Ga_(0.7)As/GaAs/Si/Ge have been simulated using a one-dimensional device simulator called personal computer oe dimension (PC1D). The dependencies of simulated current density-voltage (J-V) and external quantum efficiency (EQE) results on the thicknesses of each sub-cell have been thoroughly analyzed to determine the preferred thickness. Compared to Al_(0.3)Ga_(0.7)As/GaAs/Ge (1.5/5/50 μm), Al_(0.3)Ga_(0.7)As/GaAs/Si (1.5/5/180 μm) has an increase of 0.36 V for open-circuit voltage (V_(oc)) but a slight decrease of 1.55 mA/cm~2 for short-circuit current density (J_(sc)). Subsequently, a monolithic InGaP/GaAs/InGaNAsSb (1.9/1.42/1 eV, 3 J) cell has been mechanically stacked on a Ge cell with four terminals. The J_(sc) value of 14 mA/cm~2 and 6.5 mA/cm~2 is calculated for each sub-cell of 3 J cell and bottom Ge cell with integration of EQE measurements. In addition, the TiO_2/SiO_2/TiO_2 (150 nm/1 μm/150 nm, trilayer) interface provides a thermal conductance (2.9 × 10~6 W K~(-1)) comparable to the direct bond interface. It is believed that the architecture of InGaP/GaAs/InGaNAsSb on the Ge cell with a trilayer interface between is the preferred choice.