Applied Physics Express (APEX) is a letters journal devoted solely to rapid dissemination of up-to-date and concise reports on new findings in applied physics. It is published daily online and monthly for the printed version. The motto of APEX is high scientific quality and prompt publication. APEX is a sister journal of the Japanese Journal of Applied Physics (JJAP) and is published by IOP Publishing Ltd on behalf of the Japan Society of Applied Physics (JSAP).
This publication is partially supported by a Grant-in-Aid for Publication of Scientific Research Results from the Japan Society for the Promotion of Science.
Number 3, March 2015 (031101-037301)
From 2014, APEX will be published by IOP Publishing on behalf of The Japan Society of Applied Physics. All submissions and refereeing will continue to be handled by the APEX Editorial Office at The Japan Society of Applied Physics. To submit a paper to APEX, please connect to the editorial web site.
In the last 30 days
Shiro Kaneko et al 2014 Appl. Phys. Express 7 035102
Silicene or germanene is a monolayer honeycomb lattice made of Si or Ge, similar to graphene made of C. In this work, we have assessed the performance potentials of silicene nanoribbon (SiNR), germanene nanoribbon (GeNR), and graphene nanoribbon (GNR), which all have a sufficient band gap to switch off, as field-effect transistor (FET) channel materials. We have demonstrated that, by comparing at the same band gap of ∼0.5 eV, the GNR FET maintains an advantage over SiNR or GeNR FETs under an ideal transport situation, but SiNR and GeNR are attractive channel materials for high-performance FETs as well.
Yongzhen Wu et al 2014 Appl. Phys. Express 7 052301
A uniform and pinhole-free hole-blocking layer is necessary for high-performance perovskite-based thin-film solar cells. In this study, we investigated the effect of nanoscale pinholes in compact TiO 2 layers on the device performance. Surface morphology and film resistance studies show that TiO 2 compact layers fabricated using atomic layer deposition (ALD) contain a much lower density of nanoscale pinholes than layers obtained by spin coating and spray pyrolysis methods. The ALD-based TiO 2 layer acts as an efficient hole-blocking layer in perovskite solar cells; it offers a large shunt resistance and enables a high power conversion efficiency of 12.56%.
Takahiro Fukui et al 2014 Appl. Phys. Express 7 055201
Nitrogen-vacancy (NV) centers in diamond have attracted significant interest because of their excellent spin and optical characteristics for quantum information and metrology. To exploit these characteristics, precise control of the orientation of the NV axis in the lattice is essential. Here we show that the orientation of more than 99% of the NV centers can be aligned along the  axis by chemical vapor deposition homoepitaxial growth on (111) substrates. We also discuss the alignment mechanisms. Our result enables a fourfold improvement in the magnetic field sensitivity and opens new avenues to the optimum design of NV center devices.
Cyril Pernot et al 2010 Appl. Phys. Express 3 061004
We report on the fabrication and characterization of AlGaN-based deep ultraviolet light-emitting diodes (LEDs) with the emission wavelength ranging from 255 to 280 nm depending on the Al composition of the active region. The LEDs were flip-chip bonded and achieved external quantum efficiencies of over 3% for all investigated wavelengths. Under cw operation, an output power of more than 1 mW at 10 mA was demonstrated. A moth-eye structure was fabricated on the back side of the sapphire substrate, and on-wafer output power measurement indicated a 1.5-fold improvement of light extraction.
Wataru Yashiro et al 2014 Appl. Phys. Express 7 032501
In X-ray grating interferometry, the fabrication of thick transmission gratings with pitches of several micrometers has been a key subject. We report on a metallic glass imprinting technique for fabricating an interferometer grating. We successfully fabricated an 8-µm-pitch, 10-µm-thick grating (26 mm 2) made of Pd 42.5Ni 7.5Cu 30P 20 metallic glass by using the technique, and as a demonstration we also performed X-ray phase imaging with the grating. The technique can be applied to fabricate not only X-ray but also neutron gratings potentially at high production rates and low costs and is expected to be widely used in the near future.
Mao-sheng Miao and Chris G. Van de Walle 2015 Appl. Phys. Express 8 024302
We propose a high-electron-mobility transistor based on the insertion of a single InN atomic layer at the AlGaN/GaN interface. Using Schrödinger–Poisson simulations and first-principles calculations, we demonstrate that this design can increase the density, localization, and mobility of the two-dimensional electron gas, hence leading to significant performance improvements.
Yuji Zhao et al 2011 Appl. Phys. Express 4 082104
We report a high-power blue light-emitting diode (LED) with a high external quantum efficiency and low droop on a free-standing (2021) GaN substrate. At a forward current of 20 mA, the LED showed a peak external quantum efficiency of 52% and an output power of 30.6 mW. In higher current density regions, the LED also showed outstanding performance, with droop ratios of 0.7% at 35 A/cm 2, 4.3% at 50 A/cm 2, 8.5% at 100 A/cm 2, and 14.3% at 200 A/cm 2. The output power and external quantum efficiency at 200 A/cm 2 were 266.5 mW and 45.3%, respectively.
Makoto Miyoshi et al 2015 Appl. Phys. Express 8 021001
Nearly lattice-matched InAlN/Al x Ga 1− x N ( x = 0.1, 0.21, and 0.34) heterostructures with a 1-nm-thick AlN interfacial layer were grown on AlN/sapphire templates by metalorganic chemical vapor deposition. Capacitance–voltage and Hall effect measurements revealed that two-dimensional electron gases (2DEGs) with high densities exceeding 2 × 10 13/cm 2 were generated at the heterointerface for all samples. It was confirmed that the generation of high-density 2DEGs can be explained as being due to internal polarization effects. The sheet resistance increased from 1,267 to 1,919 Ω/sq with the increase in Al content in the AlGaN channel, owing to the decreases in 2DEG density and mobility.
Takeo Oku et al 2014 Appl. Phys. Express 7 121601
TiO 2/CH 3NH 3PbI 3-based photovoltaic devices were fabricated. The microstructures of these devices were investigated by X-ray diffraction, transmission electron microscopy, and their calculations. Structure analysis indicated phase transformation of the perovskite structure from a tetragonal to a cubic system by annealing, which resulted in the improvement of photovoltaic properties of the devices. Effects of a multiple spin-coating method using a mixture solution were also investigated. The result showed an increase in the efficiencies of the devices, due to the microstructural change of the perovskite compound layers.
Akio Wakejima et al 2015 Appl. Phys. Express 8 026502
We demonstrate a recessed-gate normally off AlGaN/GaN high-electron-mobility transistor (HEMT) on a silicon substrate that provides a precisely controllable threshold voltage ( V th). To ensure V th uniformity, dry-etching of GaN with high etching selectivity between GaN and AlGaN is developed. Furthermore, to introduce selective dry-etching in the HEMT fabrication process, we propose a delta-doped GaN cap structure that enables negative polarization charges between the GaN cap and the AlGaN barrier to be compensated. Combining these two technologies, we fabricate recessed-gate normally off metal–insulator–semiconductor HEMTs with a subthreshold slope of 130 mV/dec and an on–off drain current ratio exceeding 10 7.
This cloud represents the 50 most popular PACS codes from the latest 250 coded articles for this journal. The larger the code the more times it occurs in those 250 articles. Click on a code to link to the articles in that category.
42.55.Px 06.30.Bp 42.65.Ky 42.55.Tv 42.15.Eq 06.30.Ft 42.60.Lh 42.65.Pc 42.30.Va 41.60.Cr 42.62.Cf 42.25.Gy 32.80.Fb 42.65.Jx 42.70.Nq 05.40.Ca 41.75.Jv 42.70.Mp 42.55.Sa 42.30.Wb 42.25.Bs 33.50.Dq 07.60.Fs 42.25.Fx 42.60.Fc 42.65.Wi 42.55.Rz 42.70.Qs 42.30.-d 42.55.Wd 42.60.Jf 24.60.Ky 42.65.Re 07.55.Db 42.25.Ja 07.50.Qx 07.07.Df 42.55.Xi 07.57.Pt 42.30.Lr 07.60.-j 42.65.Es 03.67.-a 42.60.Da 07.85.Qe 07.55.Ge 42.40.Lx 42.65.Yj 42.50.Nn 07.57.-c