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AssigneeResearch Foundation of the City University of New York
InventorsRobert R. Alfano, Shengkun Zhang, Wubao Wang
Estimating the term…
The design and operation of a p-i-n device, operating in a sequential resonant tunneling condition for use as a photodetector and an optically pumped emitter, is disclosed. The device contains III-nitride multiple-quantum-well (MQW) layers grown between a III-nitride p-n junction. Transparent ohmic contacts are made on both p and n sides. The device operates under a certain electrical bias that makes the energy level of the first excitation state in each well layer correspond with the energy level of the ground state in the adjoining well layer. The device works as a high-efficiency and high-speed photodetector with photo-generated carriers transported through the active MQW region by sequential resonant tunneling. In a sequential resonant tunneling condition, the device also works as an optically pumped infrared emitter that emits infrared photons with energy equal to the energy difference between the first excitation state and the ground state in the MQWs.
A sequential resonant tunneling device for back-side illumination, comprising an alternating semiconductor layer structure as follows:
A sequential resonant tunneling device for front-side illumination, comprising a multi-layered semiconductor structure, as follows:
A sequential resonant tunneling device for front-side illumination comprising a multilayered semiconductor structure as follows:
Dependencies are inferred from the claim text.
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Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies: superlattices;…
Nanotechnology for information processing, storage or transmission
Nanooptics
The potential barrier being a PN homojunction: the devices comprising active layers made of only Group III-V materials
Term ended 5 Dec 2023 (estimated)
1. Field of the Invention
This invention relates to sequential resonant tunneling (SRT) photodetector and emitter devices based on III-nitride multiple-quantum-well (MQW) structures; to methods of their fabrication; and to methods of their use, where III-nitride refers to compound alloys of nitride and group III elements including aluminum, gallium, and indium.
2. Description of the Related Art
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
In the drawings:
FIG. 1 is a schematic of a layered semiconductor structure according to the present invention, based on AlGaN materials with AlGaN quantum wells embedded in a AlGaN p-n junction, for use as a photodetector.
All materials of III-nitride compound semiconductors are utilizable in the design of photodetectors and emitters according to the present invention. AlGaN alloys are used in the following examples as being representative.
Layered Semiconductor Structure of a Photodetector
Referring to FIG. 1, a layered semiconductor structure of a photodetector based on AlxGa1−xN/AlyGa1−yN (x<y) MQWs according to the present invention is shown, where x and y are aluminum mole fraction in AlxGa1−xN and AlyGa1−yN layers, respectively. x and y are in the range from 0 to 1. From bottom to top, the semiconductor structure consists of a substrate crystal, a AlN semiconductor nucleation layer, heavily doped n type AlwGa1−wN material, alternately layered AlxGa1−xN and AlyGa1−yN layers, and heavily doped p type AlzGa1−zN material. The substrate is selected to be lattice-matched material to III-nitride. In the case of the device of FIG. 1, for example, bulk AlGaN materials, zinc oxide (ZnO), sapphire (Al2O3) and silicon carbide (SiC) are proper candidates. The thicknesses and the mole fractions of group III elements for different semiconductor layers vary depending on desired features of designed photodetectors.