SOLAR CELL WITH ALGAAS/SI-LAMINATED STRUCTURE

摘要

PURPOSE:To reduce unnecessary optical absorption due to a buffer layer and to obtain a highly efficient solar cell, which has absorbing characteristics matching the spectral distribution of sunlight and a simple structure, by specifying the composition ratio (y) of the p-n junction part of an AlyGa1-yAs mixed- crystal active layer within a range of 0.3=y=0.6, and specifying the composition ratio (x) of an AlxGa1-xAs mixed-crystal buffer layer as x=0.2. CONSTITUTION:An Si substrate 1 comprises a p-type part 11 (thickness of about 100mum) and an n-type part 12 (thickness of 2mum). A p-n junction 10 is formed between said parts. On the Si substrate 1, an n-type AlxGa1-xAs buffer layer 2 (x=0.2, e.g., x=0.2 and thickness of 100 nm) and an AlyGa1-yAs active layer 3 are laminated. Thus a two-stage laminated three-terminal structure is obtained. The AlyGa1-yAs active layer 3 comprises an n-type part 31 (thickness of 3mum) and a p-type part 32 (thickness of 0.2mum). A p-n junction 30 is formed between said parts. The composition ratio (y) of the part of the junction 30 is 0.3=y=0.6. When the composition ratio (y) of the upper stage AlyGa1-yAs element is made to be 0.3=y=0.6, a highly efficient cell, which has a light absorbing spectrum matching the spectral distribution of the sunlight as a whole can be constituted in correspondence with the operation of the lower stage Si element.