Hot carrier evidence in a solar cell

Abstract

According to the Shockley-Queisser theory, only photons with energy h close to a semiconductor forbidden energy gap Eg are used effectively for electrical power generation. Lower energy photons are assumed as not absorbed at all, while the residual extra energy of higher energy photons is reckoned in only through the process of carrier thermalization. On the other hand, free carriers can be heated by the infrared radiation as well as by the photons supplying the mentioned extra residual energy. The intraband light absorption has been demonstrated to rise a hot carrier photoemf across a semiconductor l-h [1, 2] and p-n [3, 4] potential barrier illuminated with a CO2 laser (h = 117 meV) radiation. The polarity of this emf is opposite to that of the classical carrier generation-induced one.