摘要 |
<p>A high efficiency solar cell (16) comprises: (a) a germanium substrate (18) having a front surface and a back surface; (b) a back-metal contact (20) on the back surface of the germanium substrate; (c) a first semiconductor cell (22) comprising (1) a GaAs p-n junction (24) formed from an n-GaAs layer (26) and a p-GaAs layer (28), the n-GaAs layer formed on the front surface of the n-germanium substrate, and (2) a p-(Al,Ga)As window layer (30), the p-(Al,Ga) As window layer (30) formed on the p-GaAs layer (28); (d) a tunnel diode (32) comprising a GaAs p+n+ junction (34) formed from a p+-GaAs layer (36) and an n+-GaAs layer (38), the p+-GaAs layer (36) formed on the p-(Al,Ga) As window layer (30); and (e) a second semiconductor cell (40) comprising (1) a (Ga,In)P p-n junction (42) formed from an n-(Ga,In)P layer (44) and a p-(Ga,In)P layer (46), the n(Ga,In)P layer (44) formed on the n+-GaAs layer (38) of the tunnel diode (32), (2) a p-(Al,In)P window or contact layer (48) formed on the p-(Ga,In)P layer (46), (3) metal grid lines (50) contacting either the p-(Ga,In)P layer (46) or the p-(Al,In)P layer (48), and (4) at least one anti-reflection coating layer (52) covering the (Al,In)P layer (48). The cascade cell of the invention permits achieving actual efficiencies of over 23 %.</p> |