A photo-voltaic cell has a first and second two-dimensional array of contact points on the first surface, each coupled to a respective one of base and emitter areas in or on the semi-conductor body. Electrically separate first and second conductor structures on the first surface emanate from each contact point, coupled to contact points of the first and second two-dimensional array respectively. The first conductor structure comprises sets of first conductor line branches, the first conductor line branches of each set branching out from a respective one of the contact points of the first two-dimensional array in at least three successive different directions at less than a hundred and eighty degrees to each other. The second conductor structure comprise second conductor line branches in at least three different directions in areas between respective pairs of adjacent non-parallel ones of the first conductor line branches, each second conductor line branch coupled at least to a respective one of the contact points of the second two-dimensional array.