| 摘要 |
A radiation-emitting PN junction is situated between a first, low-resistivity N-type, region and a second, P-type, region formed by epitaxial deposition of higher-resistivity material (either P or N type) on the first region and the diffusion of an acceptor element into the epitaxially-deposited material, the PN junction lying in the vicinity of the interface between the first region and the epitaxially-deposited material, the concentration of acceptors at the PN junction being substantially determined by the diffusion of the acceptor element, and the concentration of acceptors in the second, P-type, region being less than the concentration of donors in the first, N-type, region. In one embodiment, a semi-conductor lamp, the first region is of gallium arseno-phosphide heavily doped with tin and the epitaxially-deposited material is gallium arsenide (which has a lower energy gap) more lightly doped with zinc. Some of the tin is diffused across the interface into the gallium arsenide during a preliminary heating step, and further zinc is then diffused into the gallium arsenide so that the PN junction lies in the gallium arsenide about one micron from the interface with the gallium arseno-phosphide.
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