Electronic profile of a GaAs solar cell through photoluminescence

A p-n junction diode is modeled as three spatial regions: n type, depletion, and p type, each of which is distinguished by its own photoluminescence signature. Variation in bias alters the spatial boundaries of these three regions; variation in excitation wavelength changes the depth which is probed. A direct electronic profile of a shallow junction GaAs photovoltaic diode as a function of bias is made using these two variations. Special care is taken in forward bias to distinguish between junction and terminal voltages and to separate out electroluminescence effects.