Satrio Wicaksono

A review of advances in fatigue and life prediction of fiber-reinforced composites

This contribution is an attempt to provide a thorough review of past and current research work on fatigue and life prediction of fiber-reinforced composites. In order to summarize and present a comprehensive overview of the current state-of-the-art published works, the reviews in this contribution are broadly summarized into four groups of review; (1) fatigue of fiber-reinforced composites, (2) composite damage mechanism, (3) composite failure criteria and, (4) composite fatigue modeling and life prediction. The review will begin with a discussion of inherent and environmental factors affecting the fatigue of composites. This is followed by a rather extensive description of the composite damage mechanism and a summary of commonly used failure criteria for life prediction. And towards the end, models and methods for fatigue and life prediction of composites are summarized and discussed.

High-speed picosecond pulse response GaNAsSb p-i-n photodetectors grown by rf plasma-assisted nitrogen molecular beam epitaxy

The authors report on picosecond pulse response GaNAsSb∕GaAs p-i-n photodetectors grown by molecular beam epitaxy in conjunction with a rf plasma-assisted nitrogen source. The 2μm thick GaNAsSb photoabsorption layer contains 3.3% of N and 8% of Sb resulting in a dc photoresponse up to 1380nm wavelength. Dark current densities at 0 and −5V are 1.6×10−5 and 13A∕cm2, respectively. The GaNAsSb photodiodes exhibit a record pulse response width of only 40.5ps (full width at half maximum) corresponding to a 4.5GHz bandwidth.

Study of interdiffusion in GaAsSbN∕GaAs quantum well structure by ten-band k∙p method

The effect of annealing on the photoluminescence (PL) in GaAsSbN∕GaAs quantum wells (QWs) grown by solid-source molecular-beam epitaxy has been investigated. The annealing time and temperature are 5min and 650–750°C, respectively. Low-temperature (4K) PL peaks shift to higher energies with the annealing temperatures. An As–Sb atomic interdiffusion at the heterointerface is proposed to model this effect. The compositional profile of the QW after interdiffusion is described by an error function distribution and calculated by a ten-band k∙p method. The estimated interdiffusion constants D are ∼10−17–10−16cm2∕s in the above temperature range and an activation energy of 1±0.4eV is obtained.

Effect of growth temperature on defect states of GaAsSbN intrinsic layer in GaAs∕GaAsSbN∕GaAs photodiode for 1.3μm application

A GaAsSbN layer closely lattice matched to GaAs was used as an intrinsic layer (i layer) in a GaAs∕GaAsSbN∕GaAs p-i-n photodiode with response up to 1.3μm. Deep level transient spectroscopy measurement on the GaAs∕GaAsSbN∕GaAs reveals two types of hole traps (HTs) in the GaAsSbN i layer; (i) HT1: a shallow N-related defect state (Ea∼0.10–0.12eV) and (ii) HT2: an AsGa point defect-related midgap defect state with Ea∼0.42–0.43eV. Reduction in growth temperature from 480to420°C reduces the HT2 trap concentration from 4×1015to1×1015cm−3, while increases the HT1 trap concentration from 1×1014to7×1014cm−3. Reduction in the HT2 trap concentration following growth temperature reduction was attributed to the suppression of AsGa point defect formation. Evidence of possible change of the AsGa midgap state to a shallow level defect due to the formation of (AsGa–NAs) pairs was also suggested to have increased the HT1 trap concentration and reduced the HT2 trap concentration. An ∼4dBm improvement in photoresponse under...

Defect-induced trap-assisted tunneling current in GaInNAs grown on GaAs substrate

We present the reverse-bias current-voltage and deep-level transient spectroscopy (DLTS) characteristics of a Ga0.90In0.10N0.033As0.967∕GaAs positive-intrinsic-negative photodiode (Eg=0.92 eV) and a trap-assisted tunneling model which considers generation-recombination and tunneling mechanisms. Using trap parameters obtained from the DLTS measurement, the model generates current-voltage characteristics of the photodiode, which were found to be in good agreement with experimental current-voltage curves at different temperature. The model also suggests that high dark current at low reverse-bias voltage is caused by the presence of traps which have low activation energy. Furthermore, it is predicted that approximately ten times reduction in the dark current can be achieved when the trap concentration of type H-1 (Ea=0.15 eV) is reduced by one order. On the other hand, a similar reduction in defect concentration of type H-2 (Ea=0.40 eV), which is nearer to midgap does not produce the same effect.

Near-infrared photon upconversion devices based on GaNAsSb active layer lattice matched to GaAs

Room-temperature full GaAs-based near-infrared (NIR) upconversion has been demonstrated by connecting lattice-matched GaNAsSb/GaAs p-i-n photodetectors in series with commercial GaAs/AlGaAs light-emitting diodes (LEDs). Due to the avalanche gain in GaNAsSb/GaAs photodetectors and high internal efficiency in GaAs/AlGaAs LEDs, the upconversion efficiency of the integrated system reaches 0.048 W/W under −7 V bias, much higher than any existing NIR upconverters without amplifying structures. We have further investigated the dependence of the upconversion efficiency on applied bias and incident light intensity. The present work establishes an experimental base for direct epitaxial growth of full GaAs-based NIR upconverters with high upconversion efficiencies.

Dry Etched Waveguide Laser Diode on GeOI

We demonstrate a top-top contact, dry etched mirror facet III-V waveguide laser diode grown on germanium-on-insulator (GeOI). A 3 × InGaAs/GaAs quantum well designed to lase at 985 nm was grown on a GaAs buffer, which was lattice matched to the GeOI platform in order to realize the monolithic integration of III-V electronic and photonic devices with silicon and SiO2. Lasing occurred at ~ 985 nm with a threshold current density of ~ 2 kA/cm2. Pulsed measurements, and SEM and TEM characterization methods were used. The issue of heat transfer limited the performance of the laser.

High responsivity GaNAsSb p-i-n photodetectors at 1.3µm grown by radio-frequency nitrogen plasma-assisted molecular beam epitaxy

GaNAsSb/GaAs p-i-n photo notdetectors with an intrinsic GaNAsSb photoabsorption layer grown at 350 degrees C, 400 degrees C, 440 degrees C and 480 degrees C, have been prepared using radio-frequency nitrogen plasma-assisted molecular beam epitaxy in conjunction with a valved antimony cracker source. The i-GaNAsSb photoabsorption layer contains 3.3% of nitrogen and 8% of antimony, resulting in DC photo-response up to wavelengths of 1350 nm. The device with i-GaNAsSb layer grown at 350 degrees C exhibits extremely high photoresponsivity of 12A/W at 1.3 microm. These photodetectors show characteristics which strongly suggest the presence of carrier avalanche process at reverse bias less than 5V.

Improvement of GaInNAs p-i-n photodetector responsivity by antimony incorporation

Ga0.90In0.10N0.033As0.967/ GaAs and Ga0.96In0.04N0.028As0.967Sb0.005/ GaAs p-i-n photodetector structures. The GaInNAs and GaInNAsSb layers were grown closely lattice matched to GaAs substrate at 460 ° C using molecular beam epitaxy. Two hole-trap levels were observed in the DLTS spectra of the GaInNAs sample with activation energies of 0.152 and 0.400 eV labeled as H-1 and H-2 peak, respectively. The lower activation energy is believed to be associated with nitrogen-related defects and the higher activation energy is associated with arsenic antisite defects AsGa. Following the incorporation of Sb into GaInNAs, the H-1 peak vanished from the DLTS spectra of the GaInNAsSb sample, and the AsGa defect-related DLTS signal was significantly reduced. Analysis of the DLTS data also showed that the trap concentration related to AsGa was reduced from 2.15 10 15 to 2.58 10 14 cm �3 . The DLTS results are in good agreement with the photoresponsivity results, in which the GaInNAsSb sample showed 10 higher photoresponse compared to the GaInNAs sample. This indicates the incorporation of Sb into GaInNAs has effectively improved the p-i-n photodetector device performance.

Effect of growth temperature on closely lattice-matched GaAsSbN intrinsic layer for GaAs-based 1.3μm p-i-n photodetector

GaAsSbN layers closely lattice-matched to GaAs were studied for application as the intrinsic layer in GaAs-based 1.3μm p-i-n photodetector. The GaAsSbN was grown as the intrinsic layer for the GaAs∕GaAsSbN∕GaAs photodetector structure using solid-source molecular beam epitaxy in conjunction with a radio frequency plasma-assisted nitrogen source and valved antimony cracker source. The lattice mismatch of the GaAsSbN layer to GaAs was kept below 4000ppm, which is sufficient to maintain coherent growth of ∼0.45μm thick GaAsSbN on the GaAs substrate. The growth temperature of the GaAsSbN layer was varied from 420–480°C. All samples exhibit room temperature photocurrent response in the 1.3μm wavelength region, with dark current density of ∼0.3–0.5mA∕cm2 and responsivity of up to 33mA∕W at 2V reverse bias. Reciprocal space maps reveal traces of point defects and segregation (clustering) of N and Sb, which may have a detrimental effect on the photocurrent responsivity.