| 摘要 |
PURPOSE:To inexpensively manufacture a high efficiency battery by forming a Ge layer having a P-N junction on an inexpensive Si substrate, and forming a GaAs layer having a P-N junction on the Ge layer. CONSTITUTION:An N-type Ge layer 44 and a P-type Ge layer 45 are grown by a vapor-phase growing method with germanium gas on an N-type Si substrate 41. In this case, the thickness of the layer 44 is desirably to be several tens mum. The crystallinity of the Ge layer is improved by the thick growth, and a mechanical strength is further increased. Then, an N-type GaAs layer 47 and a P-type GaAs layer 48 are formed. The depth of the P-N junction 49 in a GaAs cell 43 is approx. 1mum or less, and the thickness of the entire GaAs cell is preferably several mum. |
