2s sEnEMiin less
`
`2EPHYSICS
`
`NEWSPAPER
`TCL 1015, Page 1
`
`

`

`An Unexercised Mind
`May Become An Incapabie Mind
`
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`
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`
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`
`TCL 1015, Page 2TCL 1015, Page 2
`
`

`

`APPLIED PHYSICS LET
`
`'EP1995
`KcCeVED
`Wrsm* LisMiHr
`cm
`.
`onmH$m
`OPTICS
`PiTfS&ffSSg
`V> ;•
`1797 Chirp of passively and actively mode-locked sermconductor lasersVX
`' t ' ■
`'- * '1 > ''di-
`1800 Grating coupled multicolor quantum well infrared photodetectors
`
`K j
`
`- '-5/
`
`67, No. 13, 25 September 1995
`
`CODEN: APPLAB
`
`ISSN: 0003-6951
`
`1803 Pulsed laser deposition of BaTiOs thin films and their optical
`properties
`1806 Optical heterodyne detection of 60 GHz electro-optic modulation
`from polymer waveguide modulators
`
`1809 Picosecond spectroscopy of optically modulated high-speed laser
`diodes
`
`1812 Double layers of single domains formed by rapid thermal annealing
`of proton-exchanged LiTaOs
`1815 Laser diode pumped 106 mW blue upconversion fiber laser
`
`1818 New nonlinear optical crystal: Cesium lithium borate
`
`1821 Wavelength insensitive passive polarization converter fabricated by
`poled polymer waveguides
`1824 Physical modeling of pyrometric interferometry during molecular
`beam epitaxial growth of lll-V layered structures
`
`FLUIDS, PLASMAS, AND ELECTRICAL DISCHARGES
`1827 Generalized formula for the surface stiffness of fluid-saturated
`porous media containing parallel pore channels
`
`CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES
`1830 Characterization of structural defects in wurtzite GaN grown on 6H
`SiC using plasma-enhanced molecular beam epitaxy
`
`1833 Stress evolution during the growth of ultrathin layers of iron and
`iron silicide on Si(111)
`1836 Epitaxial electro-optical Sr,fBai_;,Nb206 films by single-source
`plasma-enhanced metalorganic chemical vapor deposition
`
`1839 Effects of hydrogen addition and growth-etch cycling on the
`oxy-acetylene torch deposition of homoepitaxial diamond
`1841 Electron spin resonance observations of excimer-laser-induced
`paramagnetic centers in tellurite glasses
`1844 Surface acoustic wave reflections from a proton exchanged dispersive
`dot array
`1847 Evidence of interstitial location of Er atoms implanted into silicon
`
`(Continued)
`
`
`
`TCL 1015, Page 3TCL 1015, Page 3
`
`M. Schell, J. Yu, M. Tsuchiya,
`T. Kamiya
`M. Z. Tidrow, K. K. Choi, A. J. DeAnni,
`W. H. Chang, S. P. Svensson
`D. H. Kim, H. S. Kwok
`
`Wenshen Wang, Datong Chen,
`Harold R. Fetterman, Yongqiang Shi,
`William H. Steier, Larry R. Dalton,
`Pei-Ming D. Chow
`D. H. Sutter, H. Schneider,
`S. Weisser, J. D. Ralston,
`E. C. Larkins
`Cangsang Zhao, Reinhart Engelmann
`
`S. Sanders, R. G. Waarts,
`D. G. Mehuys, D. F. Welch
`Yusuke Mori, Ikuo Kuroda,
`Satoshi NakajimaTakatomoSasaki,
`Sadao Nakai
`Min-Cheol Oh, Sang-Yung Shin,
`Wol-Yon Hwang, Jang-Joo Kim
`H. P. Lee, E. Ranalli, X. Liu
`
`Peter B. Nagy, Adnan H. Nayfeh
`
`David J. Smith, D. Chandrasekhar,
`B. Sverdlov, A. Botchkarev,
`A. Salvador, H. Morkog
`D. Sander, A. Enders, J. Kirschner
`
`L. D. Zhu, J. Zhao, F. Wang,
`Peter E. Norris, G. D. Fogarty,
`B. Steiner, P. Lu, B. Kear, S. B. Kang,
`B. Gallois, M. Sinclair, D. Dimes,
`M. Cronin-Goiomb
`R. A. Weimer, T. P. Thorpe,
`K. A. Snail, C. E. Merzbacher
`J. D. Prohaska, J. Li, J. S. Wang,
`R. H. Bartram
`Suneet Tuli, A. B. Bhattacharyya,
`D. Fournier
`A. Kozanecki, R. J. Wiison,
`B. J. Sealy, J. Kaczanowski,
`L. Nowicki
`
`

`

`1850
`
`1853
`
`1856
`
`betweeti self-organization and size of InAs isiands
`I’
`inP(OOI) grown by gas-source moiecular beam epitaxy
`Synthesis of oriented textured diamond films on silicon via hot
`filament chemical vapor deposition
`High quality InGaN films by atomic layer epitaxy
`
`on
`
`SEMiCONDUCTORS
`1859
`Improved thermal stability of AIGaAs-GaAs quantum well
`heterostructures using a “blocking” Zn diffusion to reduce coiumn-lll
`
`1862 Near-field optical beam induced current measurements on
`heterostructures
`1865 Growth of germanium-carbon alioys on siiicon substrates bv
`molecuiar beam epitaxy
`
`1868 High-power InGaN single-quantum-well-structure blue and violet
`light-emitting diodes
`1*1® fabrication of quantum wire structures through application of
`CCI4 towards iateral growth rate controi of GaAs on patterned GaAs
`
`1874
`
`1877
`
`1880
`
`1883
`
`1885
`
`1888
`
`1891
`
`Photoluminescence studies of single submonolayer InAs structures
`grown on GaAs (001) matrix
`
`High aspect ratio submicron silicon piilars fabricated by
`photoassisted eiectrochemicai etching and oxidation
`Effects of electron cyclotron resonance plasma thermal oxidation on
`the properties of polycrystalline siiicon fiim
`Measurement of the minority carrier mobility in the base of
`heterojunction bipolar transistors using a magnetotransport method
`Comparative analysis of the optical quality of singie
`lno.1Gao.9As/Aio.33Gao 67As quantum weils grown by molecuiar beam
`epitaxy on (100) and (311) GaAs substrates
`Photoluminescence and microstructure of self-ordered grown SIGe/
`Si quantum wires
`^
`ep itS j^ ''
`grown on Si(IOO) substrates by molecular beam
`
`1894 Minority carrier lifetime improvement by gettering in Sii_;,Gejf
`
`1896 Reduction of recombination current in CdTe/CdS solar cells
`
`1899 The electronic structure and energy level alignment of porphyrin/
`metal interfaces studied by uitraviolet photoelectron spectroscopy
`
`1902 Ternperature dependence of the etch rate and selectivity of siiicon
`nitride over silicon dioxide in remote plasma NF3/CI2
`1905 Band filling at low optical power density in semiconductor dots
`
`1908
`
`Investigation of high-field domain formation in tight-binding
`superlattices by capacitance—voltage measurements
`1911 High quality singie and double two-dimensional electron gases
`grown by metalorganic vapor phase epitaxy
`
`(Continued)
`
`A. Ponchet, A. Le Corre, H. L’Haridon,
`B. Lambert, S. Salaun
`Qijin Chen, Jie Yang, Zhangda Lin
`
`K. S. Boutros, F. G. McIntosh,
`J. C. Roberts, S. M. Bedair,
`E. L. Finer, N. A. El-Masry
`
`M. R. Krames, A. D. Minervini,
`E. I. Chen, N. Holonyak, Jr.,
`J. E. Baker
`M. S. Unlii, B. B. Goldberg,
`W. D. Herzog, D. Sun, E. Towe
`J. Kolodzey, P. A. O’Neil, S. Zhang,
`B. A. Orner, K. Roe, K. M. Unruh,
`C. P. Swann, M. M. Waite,
`S. Ismat Shah
`Shuji Nakamura, Masayuki Senoh,
`Naruhito Iwasa, Shin-ichi Nagahama
`Yong Kim, Yang Keun Park,
`Moo-Sung Kim, Joon-Mo Kang,
`Seong-ll Kim, Seong-Min Hwang,
`Suk-Ki Min
`Wei Li, Zhanguo Wang, Jiben Liang,
`Bo Xu, Zhanping Zhu, Zhiliang Yuan,
`Jian Li
`H. W. Lau, G. J. Parker, R. Greet,
`M. Rolling
`Jung-Yeal Lee, Chul-Hi Han,
`Choong-Ki Kim, Bok-Ki Kim
`Y. Betser, D. Ritter, G. Bahir,
`S. Cohen, J. Sperling
`O. Brandt, K. Kanamoto, M. Tsugami,
`T. Isu, N. Tsukada
`
`A. Hartmann, C. Dieker, R. Loo,
`L. Vescan, H. Liith, U. Bangert
`X. M. Fang, T. Chatterjee,
`P. J. McCann, W. K. Liu, M. B. Santos,
`W. Shan, J. J. Song
`B. R. Losada, A. Moehlecke,
`R. Lagos, A. Luque
`D. M. Oman, K. M. Dugan,
`J. L. Killian, V. Ceekala,
`C. S. Ferekides, D. L. Morel
`S. Narioka, H. Ishii, D. Yoshimura,
`M. Sei, Y. Ouchi, K. Seki,
`S. Hasegawa, T. Miyazaki, Y. Harima,
`K. Yamashita
`J. Staffa, D. Hwang, B. Luther,
`J. Ruzyllo, R. Grant
`P. Castrillo, D. Hessman, M.-E. Pistol,
`S. Anand, N. Carlsson, W. Seifert,
`L. Samuelson
`Z. Y. Han, S. F Yoon,
`K. Radhakrishnan, D. H. Zhang
`H. C. Chui, B. E. Hammons,
`J. A. Simmons, N. E. Harff,
`M. E. Sherwin
`
`
`
`TCL 1015, Page 4TCL 1015, Page 4
`
`

`

`1914
`
`Intensity-dependent energy and line shape variation of donor-
`acceptor-pair bands in ZnSe:N at different compensation leveis
`
`SUPERCONDUCTORS
`1917 Extended function of a high-T,, transition edge boiometer on a
`micromachined Si membrane
`
`1920 Deposition of high quaiity YBajCuaOy.;^ fiims on ultrathin (12 fitn
`thick) sapphire substrates for infrared detector appiications
`
`1923 Generation of 24.0 T at 4.2 K and 23.4 T at 27 K with a high-temperature
`superconductor coii in a 22.54 T background field
`1926 Biomagnetic measurements using iow-noise integrated SQUID
`magnetometers operating in iiquid nitrogen
`1929 Correiation of critical current and resistance fiuctuations in bicrystal
`grain boundary Josephson junctions
`1932 Determination of pinning strength of YBa2Cu307_,; from magnetic
`stiffness measurements
`
`1935 Disorder and synchronization in a Josephson junction piaquette
`
`MAGNETISM
`1938 History dependent domain structures in giant-magnetoresistive
`muitiiayers
`
`PAPERS IN OTHER FIELDS
`1941
`Ferroelectric phase transition temperatures of KTiOPO^ crystals
`grown from self-fluxes
`COMMENTS
`1944 Comment on “Phase transformation of cobalt induced by bail
`milling” [Appi. Phys. Lett. 66, 308 (1995)]
`1945 Response to “Comment on ‘Phase transformation of cobalt induced
`by ball milling’ ” [Appi. Phys. Lett. 67, 1944 (1995)]
`
`1947 CUMULATIVE AUTHOR INDEX
`
`P. Baume, J. Gutowski, D. Wiesmann
`R. Heitz, A. Hoffmann, E. Kurtz,
`D. Hommel, G. Landwehr
`
`H. Neff, J. Laukemper, G. Hefle,
`M. Burnus, T. Heidenblut,
`W. Michalke, E. Steinbeiss
`A. Pique, K. S. Harshavardhan,
`J. Moses, M. Mathur, T. Venkatesan,
`J. C. Brasunas, B Lakew
`K. Ohkura, K. Sato, M. Ueyama,
`Jun Fujikami, Y. Iwasa
`M. S. Dilorio, K-Y. Yang, S. Yoshizumi
`
`A. Marx, U. Path, L. Alff, R. Gross
`
`Beate Lehndorff,
`Hans-Gerd Kurschner,
`Bernhard Lucke
`A. S. Landsberg, Y. Braiman,
`K. Wiesenfeld
`
`H. T. Hardner, M. B. Weissman,
`S. S. P. Parkin
`
`N. Angert, M. Tseitlin, E. Yashchin,
`M. Roth
`
`G. Mazzone
`
`J. Y. Huang, Y. K. Wu, H. Q. Ye
`
`
`
`A publication of the American Institute of Physics, 500 Sunnyside Blvd., Woodbury, NY 11797-2999 TCL 1015, Page 5TCL 1015, Page 5
`
`

`

`High-power InGaN single-quantum-well-structure blue and violet
`light-emitting diodes
`Shuji NakamuraMasayuki Senoh, Naruhito Iwasa, and Shin-ichi Nagahama
`Department of Research and Development, Nichia Chemical Industries, Ltd., 491 Oka, Kaminaka, Anan,
`Tokushima 774, Japan
`(Received 28 March 1995; accepted for publication 31 July 1995)
`High-power blue and violet light-emitting diodes (LEDs) based on III-V nitrides were grown by
`metalorganic chemical vapor deposition on sapphire substrates. As an active layer, the InGaN
`single-quantum-well-structure was used. The violet LEDs produced 5.6 mW at 20 mA, with a sharp
`peak of light output at 405 nm, and exhibited an external quantum efficiency of 9.2%. The blue
`LEDs produced 4.8 mW at 20 mA and sharply peaked at 450 nm, corresponding to an external
`quantum efficiency of 8.7%. These values of the output power and the quantum efficiencies are the
`highest ever reported for violet and blue LEDs. © 1995 American Institute of Physics.
`
`Much research has been conducted on high-brightness
`blue light-emitting diodes (LEDs) and laser diodes (LDs) for
`use in full-color displays, full-color indicators, and light
`sources for lamps with the characteristics of high efficiency,
`high reliability, and high speed. For these purposes, 11-VI
`materials such as ZnSe,' SiC,^ and III-V nitride semicon­
`ductors such as GaN^ have been investigated intensively for
`a long time. However, it has been impossible to obtain high­
`brightness blue LEDs with brightness over 1 cd. As II-VI
`based materials, ZnMgSSe-, ZnSSe-, and ZnCdSe-based ma­
`terials have been intensively studied for blue and green light-
`emitting devices, and much progress has been achieved re­
`cently on green LEDs and LDs. The recent situation
`regarding performance of II-VI green LEDs is that the out­
`put power is 1.3 mW at 10 mA and that the peak wavelength
`is 512 nm."* When the peak wavelength shortens to the blue
`region, the output power decreases dramatically to about 0.3
`mW at 489 nm.'^ The lifetime of Il-VI-based light-emitting
`devices is still short, which prevents the commercialization
`of Il-VI-based devices at present. SiC is another wise band-
`gap material for blue LEDs. Current output power of SiC
`blue LEDs is only between 10 and 20 /rW because it is an
`indirect band-gap material.^
`On the other hand, there are no suitable substrates for
`III-V nitride growth without sapphire considering its high
`growth temperature and the cost of the substrate although the
`sapphire has a large lattice mismatch between GaN and sap­
`phire. Despite this large lattice mismatch, recent research on
`III-V nitrides has paved the way for the realization of high-
`quality crystals of AlGaN and InGaN, and p-type conduction
`in AlGaN.^“* Moreover, the hole-compensation mechanism
`of p-type AlGaN has been elucidated.^ High-power blue and
`blue-green LEDs with an output power over 1 mW have
`been achieved by using these techniques and are now com­
`mercially available.'®'' Although
`these
`InGaN/AlGaN
`double-heterostructure (DH) LEDs produce a high-power
`light output in the blue and blue-green regions, they have a
`broad emission spectrum [full width at half-maximum
`(FWHM)=70 nm] with the light output ranging from the
`
`“^Electronic mail: shuji@nichia.co.jp
`
`violet to the yellow-orange spectral region. This broad spec­
`trum, which results from the intentional introduction of Zn
`into the InGaN active region of the device to produce a deep-
`level emission peaking at 450 nm, makes the output appear
`whitish-blue, when the LED is viewed with the human eye.
`Therefore, blue LEDs, which produce a sharp blue emission
`at 450 nm with a narrow FWHM, have been desired for
`application to full-color LED displays. For this purpose, vio­
`let LEDs with a narrow spectrum (FWHM= 10 nm) at a peak
`wavelength of 400 nm originating from the hand-to-hand
`emission of InGaN were reported.'^ However, the output
`power of these violet LEDs was only about 1 mW, probably
`due to the formation of misfit dislocation in the thick InGaN
`active layer (about 1000 A) by the stress introduced into the
`InGaN active layer due to lattice mismatch, and the differ­
`ence in thermal expansion coefficients between the InGaN
`active layer and AlGaN cladding layers. When the thickness
`of the InGaN active layer becomes small, the elastic strain is
`not relieved by the formation of misfit dislocation and that
`the crystal quality of the InGaN active layer improves. We
`reported the high-quality InGaN multiquantum-well structure
`(MQW) with the 30 A well and 30 A barrier layers.'^ Here,
`we describe the single quantum-well structure (SQW) blue
`LEDs which have a thin InGaN active layer (about 20 A) in
`order to obtain high-power blue emission with a narrow
`emission spectrum.
`III-V nitride films were grown by the two-flow metalor­
`ganic chemical vapor deposition (MOCVD) method. Details
`of the two-flow MOCVD are described in other papers.
`The growth was conducted at atmospheric pressure. Sapphire
`with (0001) orientation (c face), which had a 2 in. diameter,
`was used as a substrate. The growth conditions of each layer
`are described in other papers.'®" In comparison with previ­
`ous InGaN/AlGaN DH LEDs, the major difference is that the
`InGaN active layer becomes a thin undoped InGaN layer.
`The blue LED device structures (Fig. 1) consists of a
`300 A GaN buffer layer grown at a low temperature
`(550 °C), a 4 /rm thick layer of n-type GaN:Si, a 1000 A
`thicklayer of n-type AlgjGaovNiSi, a 500 A thick layer
`of n-type Ino,o2Gao.98N:Si, a 20 A thick active layer of un­
`doped Ino2Gao.8N, a 1000 A
`thick
`layer of /?-type
`AlojGaojNiMg, and a 0.5 /U.m thick layer of p-type GaN:Mg.
`
`1868
`
`Appl. Phys. Lett. 67 (13), 25 September 1995
`
`0003-6951 /95/67(13)/1868/3/$6.00
`
`© 1995 American Institute of Physics
`
`TCL 1015, Page 6TCL 1015, Page 6
`
`

`

`p-electrode —
`p-GaN —
`P'AIojGaojN—^
`InoiGaos^ y
`■'■I*' 0.02^*0.98^ /
`N'o.?‘^
`n-Al„..}Ga
`n-GaN-
`GaN buffer layer.
`
`Sapphire substrate —
`
`n-electrode
`__ l _
`
`FIG. 1. The structure of SQW blue LED.
`
`The active region forms a SQW structure consisting of a 20
`A Ino2GaogN well layer sandwiched by 500 A «-type
`Ino.02Gao.98N and 1000 A p-type Alo.3Gao.7N barrier layers.
`In violet LEDs, the active layer is In0.09Ga0.9N.
`Fabrication of LED chips was accomplished as follows.
`The surface of the p-type GaN layer was partially etched
`until the n-type GaN layer was exposed. Next, a Ni/Au con­
`tact was evaporated onto the p-type GaN layer and a Ti/Al
`contact onto the n-type GaN layer. The wafer was cut into a
`rectangular shape (350 p,mX350 p.m). These chips were set
`on the lead frame, and were then molded. The characteristics
`of LEDs were measured under direct current (dc)-biased con­
`ditions at room temperature.
`Figure 2 shows the electroluminescences (EL) of the
`SQW blue LEDs in comparison with the previous Zn-doped
`InGaN/AlGaN DH blue LEDs at forward current of 20 mA.
`The peak wavelengths of both LEDs are 450 nm. The
`FWHM of the EL spectrum of the SQW blue LEDs is about
`25 nm, while that of DH LEDs is about 70 nm. The peak
`wavelength and the FWHM of SQW LEDs are almost con­
`stant when the forward current is increased to 100 mA. On
`the other hand, the peak wavelength of DH LEDs becomes
`shorter with increasing forward current and a band-to-band
`emission (around 385 nm) appears under a high-current in­
`jection condition.'^’" In the SQW blue LEDs, the active
`layer is an Ing 2GaQ gN whose band-edge emission wave­
`length is 420 nm under the stress-free.'^ On the other hand,
`the emission peak wavelength of SQW blue LEDs is 450 nm.
`The energy difference between the peak wavelength of the
`EL and the stress-free band-gap energy is approximately 190
`
`FIG. 3. Tbe output power of (a) SQW violet LED, (b) SQW blue LED, and
`(c) DH blue LED as a function of tbe forward current.
`
`meV. In order to explain this band-gap narrowing of the
`Ino 2Gao gN active layer, the quantum size effects, the exciton
`effects (Coulomb effects correlated to the electron-hole pair)
`of the active layer, and the strained effects by the mismatch
`of the lattice and the difference in thermal expansion coeffi­
`cients between well layer and barrier layers must be consid­
`ered. Among these effects, the tensile stress in the active
`layer caused by the thermal expansion coefficient difference
`between well layer and barrier layers is probably responsible
`for the band-gap narrowing of the InGaN SQW structure.
`The output power of the SQW LEDs and the DH blue
`LEDs is shown as a function of the forward current under dc
`in Fig. 3. The output power of the SQW LEDs and that of the
`DH LEDs slightly increases sublinearly up to 40 mA as a
`function of the forward current. Above 60 mA, the output
`power almost saturates, probably due to the generation of
`heat. The output power of the SQW violet LEDs is 2.8 mW
`at 10 mA, and 5.6 mW at 20 mA, which is about twice as
`high as that of the DH blue LEDs. The external quantum
`efficiency is 9.2% at 20 mA. The output power of SQW blue
`LEDs with a peak wavelength of 450 nm is 4.8 mW at 20
`mA and the external quantum efficiency is 8.7%.
`A typical example of the / - V characteristics of the SQW
`blue LEDs is shown in Fig. 4. The forward voltage is 3.1 V
`
`gBBgjgg Y: 5mA/div.
`
`FIG. 2. Electroluminescence spectra of (a) SQW blue LED and (b) DH blue
`LED at a forward current of 20 mA.
`
`FIG. 4. Typical l - V cbaracteristics of SQW blue LED.
`
`X: IV/div.
`
`Appl. Phys. Lett., Vol. 67, No. 13, 25 September 1995
`
`1869
`Nakamura ef a/.
`
`TCL 1015, Page 7TCL 1015, Page 7
`
`

`

`at 20 mA. This forward voltage is the lowest value ever
`reported for III-V nitride LEDs.
`In summary, high-power InGaN SQW blue and violet
`LEDs were fabricated. The output power of the violet LEDs
`was 5.8 mW and the external quantum efficiency was as high
`as 9.2% at a forward current of 20 mA at room temperature.
`The peak wavelength and the FWHM were 405 and 20 nm,
`respectively, and those of blue LEDs were 450 and 25 nm,
`respectively. Such LED performances of quantum well struc­
`tures will pave the way for the realization of blue LDs based
`on III-V nitride materials in the near future.
`
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