Bi-directional dual-color light emitting device and systems for use thereof

• US 20160005921A1
• Filed: 07/01/2015
• Published: 01/07/2016
• Est. Priority Date: 07/03/2014
• Status: Active Grant

• Current Assignee: Power Photonics Corp.
• Original Assignee: Power Photonics Corp.
• Inventors: Suchalkin, Sergey, Belenky, Gregory, Shterengas, Leon, Westerfeld, David
• Granted Patent: US 9,590,140 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 2021/3181 using LEDs
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: H01L 33/0025 comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table

Abstract

An LED optimized for use in low-cost gas or other non-solid substance detection systems, emitting two wavelengths (“colors”) of electromagnetic radiation from the same aperture is disclosed. The LED device emits a light with a wavelength centered on an absorption line of the target detection non-solid substance, and also emits a reference line with a wavelength that is not absorbed by a target non-solid substance, while both wavelengths are transmitted through the atmosphere with low loss. Since the absorption and reference wavelengths are emitted from the same exact aperture, both wavelengths can share the same optical path, reducing the size and cost of the detector while also reducing potential sources of error due to optical path variation.

Claims

1. A two-terminal light emitting semiconductor device producing a light of two different wavelengths depending on a polarity of an applied electric bias, comprising two active regions with efficient radiative carrier recombination, each of the said active regions sandwiched between two carrier supply regions of different carrier types, the said active regions sharing one of the carrier supply regions and conducting electric current at both polarities of the electric bias.

2. A semiconductor device of claim 1 where at least one of the said active regions comprises a bulk material with efficient radiative carrier recombination.

3. A semiconductor device of claim 1 where at least one of the said active regions comprises a structure with localized quantum state of the carrier, a structure selected from the group of quantum well and superlattice.

4. A semiconductor device of one of the claim 2 or 3 where each of the said active regions emits light when biased in forward direction with respect to the polarity of adjacent carrier supply regions, and efficiently non-radiatively conducts electric current when biased in reverse direction with respect to the polarity of adjacent carrier supply regions.

5. A semiconductor device of the claim 4 where the shared carrier supply region is p-type and does not have an external electrical connection attached to it, and the other two carrier supply regions are n-type and have an external electrical connections (terminals) attached to them.

6. A semiconductor device of the claim 5, with the said active regions producing the light of the wavelength in the infrared region of the spectra, when biased in forward direction with respect to the polarity of adjacent carrier supply regions.

7. A semiconductor device of the claim 6 where the wavelength of the light produced by both said active regions belongs to an atmospheric transparency window.

8. A semiconductor device of the claim 7 where the wavelength of the light produced by one of the said active regions belongs to a transparency window of a pre-selected non-solid substance, while the light produced by the other of the said active regions is effectively absorbed by that said pre-selected non-solid substance.

9. A semiconductor device of the claim 4 where the shared carrier supply region is n-type and does not have an external electrical connection attached to it, and the other two carrier supply regions are p-type and have an external electrical connections (terminals) attached to them.

10. A semiconductor device of the claim 9, with the said active regions producing the light of the wavelength in the infrared region of the spectra, when biased in forward direction with respect to the polarity of adjacent carrier supply regions.

11. A semiconductor device of claim 10 where the wavelength of the light produced by both said active regions belongs to an atmospheric transparency window.

12. A semiconductor device of claim 11 where the wavelength of the light produced by one of the said active regions belongs to a transparency window of a pre-selected non-solid substance, while the light produced by the other of the said active regions is effectively absorbed by that said pre-selected non-solid substance.

13. A non-solid substance detection system comprising the semiconductor device of claim 8, detecting the presence of the non-solid substance that is transparent to a wavelength of the light emitted by one of the said active regions, and is efficiently absorbing the light emitted by another of the said active regions.

14. A non-solid substance detection system comprising the semiconductor device of claim 12, detecting the presence of the non-solid substance that is transparent to a wavelength of the light emitted by one of the said active regions, and is efficiently absorbing the light emitted by another of the said active regions.