The invention discloses a wide-
band gap multi-
heterojunction tunnel junction structure, which comprises four functional
layers from the first to the fourth, wherein the first functional layer is provided with a first
band gap and a first type
doping; the second functional layer is provided with a second
band gap smaller than the first band gap and the first type
doping; the third functional layer is provided with a third band gap and a second type
doping; and the fourth functional layer is provided with a fourth band gap larger than the third band gap and the second type doping. Due to the adoption of the structure provided by the invention, the problem that the
peak current density of the wide-band
tunnel junction in the prior art is low is solved, four functional
layers are adopted to form the
tunnel junction structure, and hetero junctions are formed among the functional
layers, so that the peak
tunneling current can be improved either by the
band offset of a pN type or nP type
heterojunction structure, or by the carrier compensation, which is realized through the injection effect of a carrier of a Pp type or Nn type
heterojunction structure, and accordingly, the series resistance value is smaller. Therefore, the wide-band gap multi-heterojunction tunnel junction structure can be applied to a high-power
concentrator solar cell.