Experimental Analysis of Majority Carrier Transport Processes at Heterointerfaces in Photovoltaic Devices

The transport processes of majority carriers through potential barriers at heterointerface layers of GaAs solar cell structures are experimentally analyzed by optical-injection-dependent and temperature-dependent current–density voltage (J–V) measurements. It is shown that the influence of front-surface-field and back-surface-field layers on majority carrier transport mechanisms is most pronounced in the J--V characteristics when high-concentration or low-temperature operating conditions are concerned. A method to determine the effective majority carrier potential barrier height at heterointerfaces is described and exemplified at GaAs solar cells structures. Discussion is provided on how a significant improvement of the majority carrier flow at heterointerfaces is achievable by modification of the doping concentration profiles of the solar cell structure. The results are also applicable to other optoelectronic devices such as light-emitting diodes or detectors.