TCAD Modeling and Simulation of Dark Current-Voltage Characteristics in High-Periodicity InGaN/GaN Multiple-Quantum-Wells (MQWs) Solar Cells

Gallium nitride (GaN) based high periodicity indium/GaN multiple quantum wells solar cells have recently been proposed for different applications: from operation in harsh environments, like space applications, to their use in concentrator solar harvesting system and wireless power transfer system. In this article, we extensively investigate the mechanisms, which influence the in-dark current-voltage characteristics of these device under no excitation by means of experimental measurements and numerical simulations performed with the technology computer-aided design (TCAD) Sentaurus suite from Synopsys. Two different nonlocal models are introduced: the first one considers intrabarrier tunneling, which was found to be the dominant conduction mechanism for voltages above the main diode turn-on; the second model considers trap-assisted tunneling, implemented through traps uniformly distributed in space and energy, to reproduce the current flow in the sub turn-on region. A good matching is obtained between the experimental and simulated electrical characteristics, by considering these nonlocal models in addition to the thermionic escape.