Peculiarities of solar elements based on narrow-band-gap semiconductors

Ideas concerning the development of solar elements with structures consisting of a p-n junction on a narrow-band-gap semiconductor and a cascade of frontal pw - pn- heterojunctions on wide-band-gap semiconductors, as well as the possibility of multiple generation of electron-hole pairs as the result of acceleration of photoelectrons in the fields of pw - pn- heterojunctions, are proposed. The approximate evaluation of the efficiency of these solar elements shows that they can be more effective than silicon solar elements. (author)