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.
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.
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.
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.
Daiki Hatanaka et al 2014 Appl. Phys. Express 7 125201
A phonon waveguide (WG) constructed via a one-dimensional array of mechanical resonators is used to access a localized mechanical resonator. This resonator plays the role of a memory node in which binary information can be written, stored, and read via the mobile mechanical excitations in the phonon WG. The phonon WG-localized resonator architecture demonstrates the viability of mechanical circuits for information processing applications.
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.
Konosuke Aoyama et al 2014 Appl. Phys. Express 7 122701
We demonstrate the linewidth reduction of a laser diode from 6.4 MHz to 6.5 kHz using a compact coherent optical negative feedback system, which consists of only a lens and an optical filter. The FM noise power spectral density (PSD) and the relative intensity noise (RIN) of the laser output are measured to discuss the performance of the system. The FM noise PSD is reduced by ∼30 dB at <100 MHz. The RIN of ∼130 dB/Hz is not found to be increased by the feedback at <7 GHz, where the system is driven under negative feedback conditions.
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.
Hsien-Chin Chiu et al 2015 Appl. Phys. Express 8 011001
A micromachined AlGaN/GaN high-electron-mobility transistor (HEMT) on a Si substrate with diamondlike carbon/titanium (DLC/Ti) heat-dissipation layers was investigated. Superior thermal conductivity and thermal expansion coefficient similar to that of GaN enabled DLC/Ti to efficiently dissipate the heat of the GaN power HEMT through the Si substrate via holes. This HEMT with DLC design also maintained a stable current density at bending conditions (strain: 0.01%). Infrared thermographic imaging showed that the thermal resistance of standard multi-finger power HEMT layer was 13.6 K/W and it improved to 5.3 K/W because of the micromachining process with a backside DLC/Ti composite layer. Thus, the proposed DLC/Ti heat-dissipation layer realized efficient thermal management in GaN power HEMTs.
Ryohei Tanuma et al 2014 Appl. Phys. Express 7 121303
We demonstrate the three-dimensional imaging of threading screw dislocations (TSDs), threading edge dislocations (TEDs), and basal plane dislocations (BPDs) in 4H-SiC using two-photon-excited band-edge photoluminescence. Three-dimensional images of TSDs, TEDs, and BPDs are obtained successfully as dark contrasts on a bright background of band-edge emission. Dislocation images extending ∼200 µm from the surface are demonstrated. The tilt angles of TSDs and TEDs in 4H-SiC epilayers are also measured, and the mechanisms governing the line directions of TEDs and TSDs are discussed.
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 42.25.Gy 32.80.Fb 42.79.Fm 42.70.Nq 42.65.Jx 05.40.Ca 42.70.Mp 42.55.Sa 42.30.Wb 42.25.Bs 33.50.Dq 07.60.Fs 42.25.Fx 42.60.Fc 42.55.Rz 42.70.Qs 42.55.Wd 42.30.-d 42.60.Jf 24.60.Ky 42.65.Re 07.55.Db 42.79.Dj 07.50.Qx 42.40.Kw 07.07.Df 42.55.Xi 07.57.Pt 42.30.Lr 42.72.Ai 07.60.-j 42.65.Es 03.67.-a 42.60.Da 42.65.Yj 42.40.Lx 07.55.Ge 07.85.Qe 42.50.Nn 07.57.-c