Effect of Ni Seed Layer for Electroplating 63Ni in Beta Voltaic Battery

Ni seed layers with a thickness of 200, 500, and 1000 A were deposited by e-beam irradiation on a single trench P-N absorber in a beta voltaic battery. The optimum thickness of 63Ni on the seed layer was determined to be about 2 μm regarding the minimum self-shielding effect of a beta-ray (β-ray). The electroplating was carried out using two-step processes such as preparation of ionic solution including 63Ni, and coating processes on the seed layer. The electroplating of Ni on the seed layer was carried out at current density of 20 mA/cm2. Both the conductivity and uniformity of the seed layer are enhanced, as the thickness of deposit layer is increased. However, self-shielding of β-ray from measuring photo-voltaic (I-V curves) is significantly increase, as the thickness of the seed layer become thick. To fabricate the effective β-voltaic battery, the thickness of seed layer about 500 A has been determined in view of both preventing self-shielding β-ray and increasing conductivity on the surface.