APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

16 Oct 2006

Volume 89, Issue 16, Articles (16xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 89, 164101 (2006); http://dx.doi.org/10.1063/1.2362602 (3 pages)

Yen-Wen Lu and Chang-Jin(CJ) Kim
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Organic diodes as monolithically integrated surface plasmon polariton detectors

H. Ditlbacher, F. R. Aussenegg, J. R. Krenn, B. Lamprecht, G. Jakopic, and G. Leising

Appl. Phys. Lett. 89, 161101 (2006); http://dx.doi.org/10.1063/1.2362975 (3 pages) | Cited 21 times

Online Publication Date: 16 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors show that organic p/n heterojunction diodes enable the direct electric detection of surface plasmon polaritons (SPPs). The organic diodes are built from two organic semiconductor thin film layers with an area of 150×500 μm2 deposited on an extended silver thin film. Besides serving as the bottom electrode of the diode this silver thin film is as well a waveguide feeding SPPs to the diode area. The authors visualize the direct SPP detection by a spatially resolved induced current map.
Show PACS
85.30.Kk Junction diodes
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
85.60.Gz Photodetectors (including infrared and CCD detectors)

Low threshold current density distributed feedback quantum cascade lasers with deep top gratings

Gangyi Xu, Aizhen Li, Yaoyao Li, Lin Wei, Yonggang Zhang, Chun Lin, and Hua Li

Appl. Phys. Lett. 89, 161102 (2006); http://dx.doi.org/10.1063/1.2362580 (3 pages) | Cited 6 times

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on pulsed and continuous-wave operation of single mode tunable distributed feedback quantum cascade lasers at λ ∼ 7.7 μm. A deep top grating and a thin heavily doped InP layer beneath the grating are formed in the upper cladding to obtain simultaneously a strong feedback effect and a low waveguide loss. A “three-well vertical transition” active region is used with a low doped injector. In pulsed operation, a very low threshold current density of 970 A/cm2 and a peak power of 75 mW are achieved at 300 K. Reliable single mode emission with a side mode suppression ratio of ∼ 30 dB is achieved in a large temperature range (155–320 K) with a tuning range of 90 nm. The lasers operate in continuous-wave mode up to 130 K.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Fc Modulation, tuning, and mode locking
42.79.Dj Gratings
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Conditions for designing single-mode air-core waveguides in three-dimensional photonic crystals

Virginie Lousse, Jonghwa Shin, and Shanhui Fan

Appl. Phys. Lett. 89, 161103 (2006); http://dx.doi.org/10.1063/1.2362983 (3 pages) | Cited 3 times

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors present a general procedure that allows the design of single-mode air-core waveguides in three-dimensional photonic crystals. The procedure involves analyzing the modal profile of the band edge mode in the perfect crystal, identifying the regions of maximal electric-field intensity, and placing the air defects to enclose these regions. As an illustration, they present a detailed design of air-core waveguides in a recently proposed silicon body-center-cubic crystal structure that possesses a 25% complete band gap.
Show PACS
42.79.Gn Optical waveguides and couplers
42.70.Qs Photonic bandgap materials
42.15.Eq Optical system design

III/V ratio based selectivity between strained Stranski-Krastanov and strain-free GaSb quantum dots on GaAs

G. Balakrishnan, J. Tatebayashi, A. Khoshakhlagh, S. H. Huang, A. Jallipalli, L. R. Dawson, and D. L. Huffaker

Appl. Phys. Lett. 89, 161104 (2006); http://dx.doi.org/10.1063/1.2362999 (3 pages) | Cited 34 times

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors demonstrate and characterize type-II GaSb quantum dot (QD) formation on GaAs by either Stranski-Krastanov (SK) or interfacial misfit (IMF) growth mode. The growth mode selection is controlled by the gallium to antimony (III/V) ratio where a high III/V ratio produces IMF and a low ratio establishes the SK growth mode. The IMF growth mode produces strain-relaxed QDs, where the SK QDs remain highly strained. Both ensembles demonstrate strong room temperature photoluminescence (PL) with the SK QDs emitting at 1180 nm and the IMF QDs emitting at 1375 nm. Quantized energy levels along with a spectral blueshift are observed in 77 K PL. Transmission electron microscope images identify the IMF array and crystallographic shape for both types of QD formation. Atomic force microscope images characterize QD geometry and density.
Show PACS
68.65.Hb Quantum dots (patterned in quantum wells)
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
73.21.La Quantum dots

Defect reduction and efficiency improvement of near-ultraviolet emitters via laterally overgrown GaN on a GaN/patterned sapphire template

D. S. Wuu, W. K. Wang, K. S. Wen, S. C. Huang, S. H. Lin, S. Y. Huang, C. F. Lin, and R. H. Horng

Appl. Phys. Lett. 89, 161105 (2006); http://dx.doi.org/10.1063/1.2363148 (3 pages) | Cited 32 times

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An approach to improve the defect density and internal quantum efficiency of near-ultraviolet emitters was proposed using a combination of epitaxial lateral overgrowth (ELOG) and patterned sapphire substrate (PSS) techniques. Especially, a complementary dot array pattern corresponding to the underlying PSS was used for the ELOG-SiO2 mask design. Based on the transmission-electron-microscopy and etch-pit-density results, the ELOG/SiO2/GaN/PSS structure can reduce the defect density to a level of 105 cm−2. The internal quantum efficiency of the InGaN-based ELOG-PSS light-emitting diode (LED) sample showed three times in magnitude as compared with that of the conventional GaN/sapphire one. Under a 20 mA injection current, the output powers of ELOG-PSS, PSS, and conventional LED samples were measured to be 3.3, 2.9, and 2.5 mW, respectively. The enhanced output power could be due to a combination of the reduction in dislocation density (by ELOG) and improved light extraction efficiency (by PSS). Unlike the previous double ELOG approaches, the presented ELOG-PSS structure needs only one regrowth process and will have high potential in future high-quality ultraviolet emitters, even blue/green laser diode applications.
Show PACS
78.66.Fd III-V semiconductors
85.60.Jb Light-emitting devices
85.40.Hp Lithography, masks and pattern transfer
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
68.37.Lp Transmission electron microscopy (TEM)

Interband cascade laser operating cw to 257 K at λ = 3.7 μm

W. W. Bewley, J. A. Nolde, D. C. Larrabee, C. L. Canedy, C. S. Kim, M. Kim, I. Vurgaftman, and J. R. Meyer

Appl. Phys. Lett. 89, 161106 (2006); http://dx.doi.org/10.1063/1.2363169 (3 pages) | Cited 12 times

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A five-stage interband cascade laser with 12 μm ridge width and Au electroplating for improved epitaxial-side-up heat sinking operates cw to a maximum temperature of 257 K, where the emission wavelength is 3.7 μm. The device emits 100 mW̸facet for cw operation at 80 K, 54 mW at 200 K, and 10 mW at 250 K. The beam quality is within twice the diffraction limit for injection currents up to 14 times the lasing threshold at 120 K.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Locating hexagonal and cubic phases in boron nitride using wavelength-selective optically detected x-ray absorption spectroscopy

D. A. Evans, A. R. Vearey-Roberts, and N. R. J. Poolton

Appl. Phys. Lett. 89, 161107 (2006); http://dx.doi.org/10.1063/1.2360910 (3 pages) | Cited 1 time

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Cubic and hexagonal phases of boron nitride (c-BN and h-BN) have been identified and located using optically detected x-ray absorption spectroscopy (ODXAS). Each phase was identified by distinct resonance features in the B K-edge absorption spectra. In a mixed-phase sample of predominantly c-BN, combined ODXAS and electron yield measurements suggested near-surface localization of h-BN. Using x-ray excited luminescence, emission bands due to each phase were identified and applied in wavelength-selective ODXAS to locate surface and bulk h-BN phases. These combined techniques provide a method of correlating the local structure and optical emission in these wide-gap semiconductors.
Show PACS
78.70.Dm X-ray absorption spectra
78.55.Cr III-V semiconductors

High intensity light propagation in InAs

Srinivasan Krishnamurthy, Zhi Gang Yu, Shekhar Guha, and Leo Gonzalez

Appl. Phys. Lett. 89, 161108 (2006); http://dx.doi.org/10.1063/1.2363970 (3 pages) | Cited 6 times

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors present their experimental and theoretical results on nonlinear absorption of light in InAs. The nonlinear variation of output intensity as a function of input intensity and time are calculated by solving four coupled rate equations simultaneously. All required quantities, including two-photon absorption, free-carrier absorption, Auger and radiative recombination lifetimes, and intrinsic carrier densities, have been obtained from the underlying band structures. The calculated thickness and energy-dependent output intensities in InAs agree very well with the values measured in their pump-probe experiments.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
79.60.Bm Clean metal, semiconductor, and insulator surfaces
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.20.At Surface states, band structure, electron density of states

Fiber Bragg grating microphone system

Lipi Mohanty, Liang Mong Koh, and Swee Chuan Tjin

Appl. Phys. Lett. 89, 161109 (2006); http://dx.doi.org/10.1063/1.2363977 (3 pages) | Cited 5 times

Online Publication Date: 17 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A fiber Bragg grating microphone has been developed and tested in the audible frequency range. The fiber Bragg grating is longitudinally attached to a membrane that vibrates in response to acoustic vibrations and is prestrained. The frequency and amplitude of the sound are encoded in the wavelength shift. The microphone can also pick up voices dynamically from a distance of a few meters. The simplicity of principle and structure of this fiber grating sensor provides scope for commercialization as an optical microphone.
Show PACS
42.81.Pa Sensors, gyros
42.79.Jq Acousto-optical devices
42.79.Dj Gratings
42.81.Wg Other fiber-optical devices
43.38.Zp
43.58.-e

Microdroplet deposition of copper film by femtosecond laser-induced forward transfer

Li Yang, Ching-yue Wang, Xiao-chang Ni, Zhi-jun Wang, Wei Jia, and Lu Chai

Appl. Phys. Lett. 89, 161110 (2006); http://dx.doi.org/10.1063/1.2364457 (3 pages) | Cited 9 times

Online Publication Date: 18 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Copper microdroplets were deposited onto a quartz substrate by the laser-induced forward transfer (LIFT) using laser pulses of 148 fs at a center wavelength of 775 nm. The droplets with 2–3 μm diameters were transferred at a laser pulse energy slightly above the threshold at which the copper film could be removed completely. The droplet formation was a result of the blow-off of a molten film from the quartz substrate by a compressive stress of plasma when the free surface was melted and was different from the microdroplet formation by the LIFT technique using nanosecond laser pulse.
Show PACS
81.15.Fg Pulsed laser ablation deposition
68.55.A- Nucleation and growth
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Highly efficient optical pumping of photonic crystal nanocavity lasers using cavity resonant excitation

Masahiro Nomura, Satoshi Iwamoto, Masao Nishioka, Satomi Ishida, and Yasuhiko Arakawa

Appl. Phys. Lett. 89, 161111 (2006); http://dx.doi.org/10.1063/1.2369543 (3 pages) | Cited 13 times

Online Publication Date: 18 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors demonstrate highly efficient optical pumping of photonic crystal (PhC) nanocavity lasers with InGaAs single quantum wells (QWs) using cavity resonant excitation at 10 K. The laser threshold power is largely reduced when the central wavelength of the excitation pulse is resonant with a higher-order cavity mode. The localized excitation by the cavity resonant effect increases the effective absorption of the QW region in the nanocavity. The direct photocarrier generation in the QW also results in the highly efficient optical pumping. This cavity resonant excitation technique can lower the laser threshold of PhC nanocavity lasers and avoid detrimental device heating.
Show PACS
42.55.Tv Photonic crystal lasers and coherent effects
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.70.Qs Photonic bandgap materials

Highly sensitive organic ultraviolet optical sensor based on phosphorescent Cu (I) complex

Zhiguo Kong, Wenlian Li, Guangbo Che, Bei Chu, Defeng Bi, Liangliang Han, Lili Chen, Zhizhi Hu, and Zhiqiang Zhang

Appl. Phys. Lett. 89, 161112 (2006); http://dx.doi.org/10.1063/1.2364156 (3 pages) | Cited 6 times

Online Publication Date: 18 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ultraviolet light-sensitive organic optical sensor based on photovoltaic diode was demonstrated by using a phosphorescent Cu complex and a diamine derivative as electroacceptor and electrodonor, respectively. The Cu complex is Cu(DPEphos)((Bphen))BF4, in which DPEphos and Bphen denote 6,7-dicyanodipyrido [2,2-d:2′,3′-f] quinoxaline and bathophenanthroline. And the diamine derivative, m-MTDATA, is 4, 4′,4″-tris-(2-methylphenyl phenylamino) triphenylamine. The sensor is highly sensitive to UV light band from 300 to 420 nm while it has almost no response to the visible light, and under illumination of 365 nm light with power of 1.7 mW/cm2, the sensor exhibits an open circuit voltage of 1.86 V, a short circuit current of 105.3 μA/cm2, a fill factor of 0.246, and a power conversion efficiency of 2.83%. The dependences of ultraviolet responsive sensitivity on illumination intensity and working temperature were also discussed.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
85.60.Gz Photodetectors (including infrared and CCD detectors)

Low loss contacts for organic semiconductor lasers

P. Görrn, T. Rabe, T. Riedl, W. Kowalsky, F. Galbrecht, and U. Scherf

Appl. Phys. Lett. 89, 161113 (2006); http://dx.doi.org/10.1063/1.2360936 (3 pages) | Cited 18 times

Online Publication Date: 19 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
For the realization of electrically driven organic semiconductor lasers low loss contacts for charge injection are essential. The authors show that the addition of thin, highly transparent conducting layers (thickness on the order of 10–20 nm) of aluminum doped zinc oxide to a planar waveguide structure formed by a 145 nm thick polymer active layer leaves the threshold for the onset of amplified spontaneous emission almost unchanged. This finding paves the way towards electrically driven organic lasers without the need for unrealistically thick organic spacers to keep the waveguide mode away from the contacts.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.82.Gw Other integrated-optical elements and systems

Diffraction-aided laser-induced microstructuring of thin TiO2 films on glass

O. Van Overschelde and M. Wautelet

Appl. Phys. Lett. 89, 161114 (2006); http://dx.doi.org/10.1063/1.2364462 (3 pages) | Cited 4 times

Online Publication Date: 20 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thin films of TiO2 are deposited by magnetron sputtering on glass substrate and are irradiated by ultraviolet radiation using a KrF excimer laser. These thin films are patterned with a razor blade placed in the way of the radiation. When the fluence is in the 1250–1550 mJ/cm2 range, a regular structure appears, with controlled ablation of the films. It is shown that above a critical local fluence, the ablated depth varies linearly with the local fluence. The proportionality factor is shown to be equal to two photons per evaporated molecule.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
52.38.Mf Laser ablation

Large electro-optic effect in tensile strained Ge-on-Si films

Samerkhae Jongthammanurak, Jifeng Liu, Kazumi Wada, Douglas D. Cannon, David T. Danielson, Dong Pan, Lionel C. Kimerling, and Jurgen Michel

Appl. Phys. Lett. 89, 161115 (2006); http://dx.doi.org/10.1063/1.2363948 (3 pages) | Cited 19 times

Online Publication Date: 20 October 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report the first observation of a large, strain-enhanced, electro-optic effect in the weakly absorbing regime for Ge epitaxial films grown directly on Si substrates. The field dependence of absorption in the Ge films was measured from spectral responsivity measurements of Ge-on-Si p-i-n diodes. The experimental data were analyzed using the generalized Franz-Keldysh formalism [ H. Shen and F. H. Pollak, Phys. Ref. B 42, 7097 (1990) ] and the valence band edge shifts of the light- and heavy-hole energy positions were in response to biaxial stress. With measured Δα/α ∼ 3 and derived Δn/F = 280 pm/V, the material has significant potential for field-induced phase or electroabsorption modulator devices.
Show PACS
78.66.Db Elemental semiconductors and insulators
78.20.Jq Electro-optical effects
71.20.Mq Elemental semiconductors
85.60.Dw Photodiodes; phototransistors; photoresistors
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close