초록 ▼

A dual-band HgCdTe radiation detector (10) includes a four layer n-p+-p-n+structure, grown by LPE, upon a substrate (12). The four layers are, from a bottom layer next to the substrate to the surface: (a) a MWIR radiation responsive n-type absorbing layer (14); (b) a p+cap layer (16); (c) a LWIR rad

A dual-band HgCdTe radiation detector (10) includes a four layer n-p+-p-n+structure, grown by LPE, upon a substrate (12). The four layers are, from a bottom layer next to the substrate to the surface: (a) a MWIR radiation responsive n-type absorbing layer (14); (b) a p+cap layer (16); (c) a LWIR radiation responsive p-type layer (18); and (d) an n+top layer (20). The n+top layer has a compositional profile that is similar to the p-type cap layer. Operation of this structure involves biasing the top layer positive with respect to the bottom layer, which results in the collection of LWIR-generated electrons in the p-type layer. Biasing the top layer negative with respect to the bottom layer results in MWIR-generated holes being collected by the bottom n-p+junction. In this mode, however, the detector structure rejects collection of LWIR-generated electrons because a compositional profile of the two p-type layers prevents the electrons from drifting to the bottom n-p+junction and being collected.

대표청구항 ▼

A radiation detector structure responsive to electromagnetic radiation within two spectral bands, said radiation detector structure including a plurality of adjacently disposed layers of Group II-VI semiconductor material and comprising: a first layer comprised of Group II-VI semiconductor material,

A radiation detector structure responsive to electromagnetic radiation within two spectral bands, said radiation detector structure including a plurality of adjacently disposed layers of Group II-VI semiconductor material and comprising: a first layer comprised of Group II-VI semiconductor material, said first layer being doped to provide a first type of electrical conductivity and having a bandgap selected for absorbing radiation within a first spectral band; a second layer overlying said first layer, said second layer being comprised of Group II-VI semiconductor material, said second layer being doped to provide a second type of electrical conductivity that is opposite the first type of electrical conductivity said first and second layers forming a first junction; a third layer overlying said second layer, said third layer being comprised of Group II-VI semiconductor material, said third layer being doped to provide the second type of electrical conductivity and having a bandgap selected for absorbing radiation within a second spectral band; and a fourth layer overlying said third layer, said fourth layer being comprised of Group II-VI semiconductor material, said fourth layer being doped to provide the first type of electrical conductivity said third and fourth layers forming a second junction wherein said Group II-VI semiconductor material is comprised of Hg1-xCdxTe wherein x is varied through the thickness of the first layer in a direction toward the second layer so as to provide a decreasing bandgap energy within said first layer in the direction toward said second layer, and wherein x is varied through the thickness of the third layer in a direction toward the fourth layer so as to provide a decreasing bandgap energy within said third layer in the direction toward said fourth layer.