Numerical modeling of energy balance equations in quantum well Al xGa1-xAs/GaAs p-i-n photodiodes

The energy balance equations coupled with drift diffusion transport equations in heterojunction semiconductor devices are solved modeling hot electron effects in single quantum well p-i-n photodiodes. The transports across the heterojunction boundary and through quantum wells are modeled by thermionic emission theory. The simulation and experimental current-voltage characteristics of a single p-i-n GaAs/Al _xGa_1-xAs quantum well agree over a wide range of current and voltage, The GaAs/Al_xGa_1-xAs p-i-n structures with multi quantum wells are simulated and the dark current voltage characteristics, short circuit current, and open circuit voltage results are compared with the available experimental data, In agreement with the experimental data, simulated results show that by adding GaAs quantum wells to the conventional cell made of wider bandgap Al_x Ga_1-xAs, short circuit current is improved, but there is a loss of the voltage of the host cell, In the limit of radiative recombination, the maximum power point of an Al_0.35Ga_0.65As/GaAs p-i-n photodiode with 30-quantum-well periods is higher than the maximum power point of similar conventional bulk p-i-n cells made out of either host Al_0.35Ga_0.65As or bulk GaAs material