Method of producing a direct band gap in indirect band gap materials and light emitting or detecting devices fabricated therefrom
| DWPI Title: Device for implementing function of optical emitter or photodetector, comprises interlayer of indirect band gap material, where separation between two doped layers is adapted to modify band structure of interlayer |
| Abstract: A method for creating direct band gap material from indirect band gap material, the resultant direct band gap material, and corresponding optical devices are described. The method employs atomic layer doping (ALDo) to create closely spaced δ-doped layers, alternating between n-type and p-type dopants, to modify the band structure of the indirect band gap material. The spacing between adjacent δ-doped layers is between 1 and 100 Å. The dopants may, for example, include phosphorus, boron, and/or aluminum, while the indirect band gap material may, for example, include silicon and/or germanium. The method and material may alternatively employ a single dopant for all closely spaced δ-doped layers. This single dopant may, for example, be erbium. Optical devices, including emitters and photodetectors, may be formed of the created direct band gap material. Both vertical and lateral devices may be formed. |
| Use: Device for implementing a function of an optical emitter or a photodetector (claimed). Can be vertical tunnel field-effect transistors (TFETs), like optoelectronic devices. |
| Advantage: The closely spaced sheets of δ-doped silicon, alternating between n-type and p-type dopants, show that atomic-layer doping can modify the band structure of silicon to the point where direct-band-gap material can be formed. Modeling has shown that at least two dopant combinations, boron-phosphorous and aluminum-phosphorous, can produce the desired band gap properties. The modeling has also shown that a single dopant, erbium, can produce a direct band gap in silicon. |
| Novelty: Device comprises a layer of a first material, a first doped layer comprising a first dopant type, the first doped layer adjacent the layer of the first material, an interlayer of an indirect band gap material, the interlayer adjacent the first doped layer, a second doped layer comprising a second dopant type, a first electrical contact (1410A) in contact with the first doped layer, and a second electrical contact (1410B) in contact with the second doped layer. The second doped layer is adjacent to the interlayer. The second doped layer is a δ-doped layer (1420A). A separation between the first doped layer and the second doped layer is adapted to modify a band structure of the interlayer such that at least a portion of the interlayer becomes a direct band gap material. |
| Filed: 1/22/2024 |
| Application Number: US18418457A |
| Tech ID: SD 16290.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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