UWB (Ultra Wide Band) gap tunnel junction

The invention discloses a UWB (Ultra Wide Band) gap tunnel junction used for connecting with a broad-band gap sub-battery in a multijunction solar battery. The UWB gap tunnel junction comprises an n-type Alx-Ga-InP layer and a p-type Aly-Ga-As layer which are sequentially arranged in parallel, wherein x is not less than 0.01 and is not more than 0.5, and y is not less than 0.1 and is not more than 0.9; an n-type dopant is Te of which the doping concentration is 5*10 -5*10 cm ; the P-type dopant is C of which the doping concentration is 5*10 -5*10 cm ; and the thickness ranges of the n-type Alx-Ga-InP layer and the p-type Aly-Ga-As layer are 10-100nm. The UWB gap tunnel junction provided by the invention is combined by a UWB gap material, so that good electrical contact between a top battery in a UWB solar battery and a sub-battery below the UWB solar battery can be formed, and the difficult problem that a current density tunnel junction with high peak is difficultly prepared can be solved.