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PatentDOI

Blue-green laser diode

12 May 1992-Applied Physics Letters (American Institute of Physics)-Vol. 59, Iss: 11, pp 1272-1274
TL;DR: In this article, a II-VI compound semiconductor laser diode is formed from overlaying layers of material including an n-type single crystal semiconductor substrate (12), adjacent N-type and p-type guiding lasers (14), a quantum well active layer (18), and a second electrode (30) is characterized by a Fermi energy, with shallow acceptors having a shallow acceptor energy, to a net acceptor concentration of at least 1 x 1017 cm 3.
Abstract: A II-VI compound semiconductor laser diode (10) is formed from overlaying layers of material including an n-type single crystal semiconductor substrate (12), adjacent n-type and p-type guiding lasers (14) and (16) of II-VI semiconductor forming a pn junction, a quantum well active layer (18) of II-VI semiconductor between the guiding layers (14) and (16), first electrode (32) opposite the substrate (12) from the n-type guiding layer (14), and a second electrode (30) opposite the p-type guiding layer (16) from the quantum well layer (18) Electrode layer (30) is characterized by a Fermi energy A p-type ohmic contact layer (26) is doped, with shallow acceptors having a shallow acceptor energy, to a net acceptor concentration of at least 1 x 1017 cm-3, and includes sufficient deep energy states between the shallow acceptor energy and the electrode layer Fermi energy to enable cascade tunneling by charge carriers
Citations
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Journal ArticleDOI
08 Jun 2001-Science
TL;DR: Room-temperature ultraviolet lasing in semiconductor nanowire arrays has been demonstrated and self-organized, <0001> oriented zinc oxide nanowires grown on sapphire substrates were synthesized with a simple vapor transport and condensation process.
Abstract: Room-temperature ultraviolet lasing in semiconductor nanowire arrays has been demonstrated The self-organized, oriented zinc oxide nanowires grown on sapphire substrates were synthesized with a simple vapor transport and condensation process These wide band-gap semiconductor nanowires form natural laser cavities with diameters varying from 20 to 150 nanometers and lengths up to 10 micrometers Under optical excitation, surface-emitting lasing action was observed at 385 nanometers, with an emission linewidth less than 03 nanometer The chemical flexibility and the one-dimensionality of the nanowires make them ideal miniaturized laser light sources These short-wavelength nanolasers could have myriad applications, including optical computing, information storage, and microanalysis

8,592 citations

Journal ArticleDOI
Abstract: Candela‐class high‐brightness InGaN/AlGaN double‐heterostructure (DH) blue‐light‐emitting diodes(LEDs) with the luminous intensity over 1 cd were fabricated As an active layer, a Zn‐doped InGaN layer was used for the DH LEDs The typical output power was 1500 μW and the external quantum efficiency was as high as 27% at a forward current of 20 mA at room temperature The peak wavelength and the full width at half‐maximum of the electroluminescence were 450 and 70 nm, respectively This value of luminous intensity was the highest ever reported for blue LEDs

3,497 citations

Journal ArticleDOI
TL;DR: In this article, the authors compare the performance of SiC, GaN, and ZnSe for high-temperature electronics and short-wavelength optical applications and conclude that SiC is the leading contender for high temperature and high power applications if ohmic contacts and interface state densities can be further improved.
Abstract: In the past several years, research in each of the wide‐band‐gap semiconductors, SiC, GaN, and ZnSe, has led to major advances which now make them viable for device applications. The merits of each contender for high‐temperature electronics and short‐wavelength optical applications are compared. The outstanding thermal and chemical stability of SiC and GaN should enable them to operate at high temperatures and in hostile environments, and also make them attractive for high‐power operation. The present advanced stage of development of SiC substrates and metal‐oxide‐semiconductor technology makes SiC the leading contender for high‐temperature and high‐power applications if ohmic contacts and interface‐state densities can be further improved. GaN, despite fundamentally superior electronic properties and better ohmic contact resistances, must overcome the lack of an ideal substrate material and a relatively advanced SiC infrastructure in order to compete in electronics applications. Prototype transistors have been fabricated from both SiC and GaN, and the microwave characteristics and high‐temperature performance of SiC transistors have been studied. For optical emitters and detectors, ZnSe, SiC, and GaN all have demonstrated operation in the green, blue, or ultraviolet (UV) spectra. Blue SiC light‐emitting diodes (LEDs) have been on the market for several years, joined recently by UV and blue GaN‐based LEDs. These products should find wide use in full color display and other technologies. Promising prototype UV photodetectors have been fabricated from both SiC and GaN. In laser development, ZnSe leads the way with more sophisticated designs having further improved performance being rapidly demonstrated. If the low damage threshold of ZnSe continues to limit practical laser applications, GaN appears poised to become the semiconductor of choice for short‐wavelength lasers in optical memory and other applications. For further development of these materials to be realized, doping densities (especially p type) and ohmic contact technologies have to be improved. Economies of scale need to be realized through the development of larger SiC substrates. Improved substrate materials, ideally GaN itself, need to be aggressively pursued to further develop the GaN‐based material system and enable the fabrication of lasers. ZnSe material quality is already outstanding and now researchers must focus their attention on addressing the short lifetimes of ZnSe‐based lasers to determine whether the material is sufficiently durable for practical laser applications. The problems related to these three wide‐band‐gap semiconductor systems have moved away from materials science toward the device arena, where their technological development can rapidly be brought to maturity.

2,514 citations

Journal ArticleDOI
TL;DR: In this article, the InGaN multi-quantum-well (MQW) structure was used for laser diodes, which produced 215mW at a forward current of 2.3
Abstract: InGaN multi-quantum-well (MQW) structure laser diodes (LDs) fabricated from III-V nitride materials were grown by metalorganic chemical vapor deposition on sapphire substrates. The mirror facet for a laser cavity was formed by etching of III-V nitride films without cleaving. As an active layer, the InGaN MQW structure was used. The InGaN MQW LDs produced 215 mW at a forward current of 2.3 A, with a sharp peak of light output at 417 nm that had a full width at half-maximum of 1.6 nm under the pulsed current injection at room temperature. The laser threshold current density was 4 kA/cm2. The emission wavelength is the shortest one ever generated by a semiconductor laser diode.

2,100 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a new technique to fabricate p-type ZnO reproducibly, and showed high-quality undoped films with electron mobility exceeding that in the bulk.
Abstract: Since the successful demonstration of a blue light-emitting diode (LED)1, potential materials for making short-wavelength LEDs and diode lasers have been attracting increasing interest as the demands for display, illumination and information storage grow2,3,4. Zinc oxide has substantial advantages including large exciton binding energy, as demonstrated by efficient excitonic lasing on optical excitation5,6. Several groups have postulated the use of p-type ZnO doped with nitrogen, arsenic or phosphorus7,8,9,10, and even p–n junctions11,12,13. However, the choice of dopant and growth technique remains controversial and the reliability of p-type ZnO is still under debate14. If ZnO is ever to produce long-lasting and robust devices, the quality of epitaxial layers has to be improved as has been the protocol in other compound semiconductors15. Here we report high-quality undoped films with electron mobility exceeding that in the bulk. We have used a new technique to fabricate p-type ZnO reproducibly. Violet electroluminescence from homostructural p–i–n junctions is demonstrated at room-temperature.

1,964 citations

References
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Proceedings Article
01 Jan 1969

16,580 citations

Journal ArticleDOI
TL;DR: In this paper, a novel approach to produce p-type ZnSe epitaxial layers is reported which involves nitrogen atom beam doping during molecular beam epitaxy growth, which achieves acceptor concentrations as large as 3.4×1017 cm−3.
Abstract: A novel approach to producing p‐type ZnSe epitaxial layers is reported which involves nitrogen atom beam doping during molecular beam epitaxial growth. Net acceptor concentrations as large as 3.4×1017 cm−3 have been measured in nitrogen atom beam doped ZnSe/GaAs heteroepitaxial layers which represents the highest acceptor concentration reported to date for ZnSe:N epitaxial material grown by molecular beam epitaxy. In addition, light‐emitting diodes based on ZnSe:N/ZnSe:Cl, p‐n homojunctions have been found to exhibit dominant electroluminescence in the blue region of the visible spectrum at room temperature.

538 citations

Journal ArticleDOI
TL;DR: In this article, a two-step liquid phase phase-epitaxial (LPEP) injection laser with the active regions of the filamentary GaAs active regions completely surrounded by Ga1−xAlxAs was proposed.
Abstract: Buried‐heterostructure injection lasers which have the filamentary GaAs active regions completely surrounded by Ga1−xAlxAs are proposed and have been successfully fabricated by using two‐step liquid‐phase‐epitaxial techniques. The active regions of these lasers can be made extremely small and do not have dimensional unbalances encountered in conventional injection lasers. The threshold current has been reduced to a value as low as 15 mA by applying current‐confining geometry to this laser. A study of optical characteristics has revealed such improvements over ordinary lasers as Gaussian beam profile, fundamental mode (TE00) operation, mode reproducibility, and mode stability. Due to the superior thermal properties of these lasers cw operation was easily obtained.

266 citations

Journal ArticleDOI
TL;DR: Low resistivity p-type ZnSe layers have been successfully grown on GaAs substrates by metalorganic vapor phase epitaxy with the use of dimethylzinc and diethylselenide as source materials and lithium nitride as the dopant as mentioned in this paper.
Abstract: Low‐resistivity p‐type ZnSe layers have been successfully grown on GaAs substrates by metalorganic vapor phase epitaxy with the use of dimethylzinc and diethylselenide as source materials and lithium nitride as the dopant. The lowest resistivity achieved is 0.2 Ω cm, and the highest carrier concentration is 9×1017 cm−3. ZnSe p‐n diodes fabricated by this technique have shown blue emission; the spectral peak is located at 467 nm.

181 citations