Solar cell element

1. A solar cell element comprising:

a p-side electrode;

a p-type group III-group V compound semiconductor layer;

an n-type group III-group V compound semiconductor layer;

an n-side group III-group V compound electrode layer; and

a V x Zn 1-x layer; wherein

the p-side electrode is electrically connected to the p-type group III-group V compound semiconductor layer;

the p-type group III-group V compound semiconductor layer, the n-type group III-group V compound semiconductor layer, the n-side group III-group V compound electrode layer, and the V x Zn 1-x layer are stacked in this order;

the V x Zn 1-x layer is in contact with the n-side group III-group V compound electrode layer;

x represents a value of not less than 0.3 and not more than 0.99; and

the V x Zn 1-x layer has a thickness of not less than 1 nanometer and not more than 5 nanometers.

2. The solar cell element according to claim 1 , further comprising a transparent electrode layer, wherein

the V x Zn 1-x layer is interposed between the transparent electrode layer and the n-side group III-group V compound electrode layer.

3. A method for generating an electric power using a solar cell element, the method comprising:

a step (a) of preparing the solar cell element according to claim 1 ; and

a step (b) of irradiating the p-type group III-group V compound semiconductor layer and the n-type group III-group V compound semiconductor layer with incident light through the V x Zn 1-x layer and through the n-side group III-group V compound electrode layer so as to generate a voltage difference between the p-side electrode and the V x Zn 1-x layer.

4. The method according to claim 3 , wherein

the solar cell element further comprises a transparent electrode layer, and

the V x Zn 1-x layer is interposed between the transparent electrode layer and the n-side group III-group V compound electrode layer.