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 8, August 2015 (081001-087001)
The Japan Society of Applied Physics (JSAP) is pleased to announce that the Creative Commons license "CC BY" will be applied to Open Select articles to be published in Applied Physics Express (APEX) and Japanese Journal of Applied Physics (JJAP). In accordance with the policy, the copyright of Open Select articles shall belong to the authors. This policy may be retroactively applied to existing Open Select articles from July 10, 2015 with the authors' agreement.
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.
Tohru Oka et al 2015 Appl. Phys. Express 8 054101
In this paper, we report on 1.2-kV-class vertical GaN-based trench metal–oxide–semiconductor field-effect transistors (MOSFETs) on a free-standing GaN substrate with a low specific on-resistance. A redesigned epitaxial layer structure following our previous work with a regular hexagonal trench gate layout enables us to reduce the specific on-resistance to as low as 1.8 mΩ·cm 2 while obtaining a sufficient blocking voltage for 1.2-kV-class operation. Normally-off operation with a threshold voltage of 3.5 V is also demonstrated. To the best of our knowledge, this is the first report on vertical GaN-based MOSFETs with a specific on-resistance of less than 2 mΩ·cm 2.
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%.
M. Shoufie Ukhtary et al 2015 Appl. Phys. Express 8 055102
Undoped graphene is known to absorb 2.3% of visible light at a normal angle of incidence. In this paper, we theoretically demonstrate that the absorption of 10–100 GHz of an electromagnetic wave can be tuned from nearly 0 to 100% by varying the Fermi energy of graphene when the angle of incidence of the electromagnetic wave is kept within total internal reflection geometry. We calculate the absorption probability of the electromagnetic wave as a function of the Fermi energy of graphene and the angle of incidence of the wave. These results open up possibilities for the development of simple electromagnetic wave-switching devices operated by gate voltage.
Tomo-o Terasawa and Koichiro Saiki 2015 Appl. Phys. Express 8 035101
To obtain a large-area single-crystal graphene, chemical vapor deposition (CVD) growth on Cu is considered the most promising. Recently, the surface oxygen on Cu has been found to suppress the nucleation of graphene. However, the effect of oxygen in the vapor phase was not elucidated sufficiently. Here, we investigate the effect of O 2 partial pressure ( P O2) on the CVD growth of graphene using radiation-mode optical microscopy. The nucleation density of graphene decreases monotonically with P O2, while its growth rate reaches a maximum at a certain pressure. Our results indicate that P O2 is an important parameter to optimize in the CVD growth of graphene.
Nariaki Tanaka et al 2015 Appl. Phys. Express 8 071001
This paper reports on vertical GaN Schottky barrier diodes (SBDs) fabricated on a free-standing GaN substrate with different sizes of Schottky electrode. The fabricated SBDs with 3 × 3 mm 2 Schottky electrodes exhibited both a forward current of 50 A and a blocking voltage of 790 V. To our knowledge, the characteristics of operation with a simultaneous high forward current and high blocking voltage are reported for the first time for vertical GaN SBDs on free-standing GaN substrates. The dependence of these characteristics on the Schottky electrode size is also reported in detail.
Tadatsugu Minami et al 2015 Appl. Phys. Express 8 022301
In this paper, we describe efforts to enhance the efficiency of Cu 2O-based heterojunction solar cells fabricated with an aluminum–gallium–oxide (Al–Ga–O) thin film as the n-type layer and a p-type sodium (Na)-doped Cu 2O (Cu 2O:Na) sheet prepared by thermally oxidizing copper sheets. The optimal Al content [ X; Al/(Ga + Al) atomic ratio] of an Al X –Ga 1− X –O thin-film n-type layer was found to be approximately 2.5 at. %. The optimized resistivity was approximately 15 Ω cm for n-type Al X –Ga 1− X –O/p-type Cu 2O:Na heterojunction solar cells. A MgF 2/AZO/Al 0.025–Ga 0.975–O/Cu 2O:Na heterojunction solar cell with 6.1% efficiency was fabricated using a 60-nm-thick n-type oxide thin-film layer and a 0.2-mm-thick Cu 2O:Na sheet with the optimized resistivity.
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.
Bing-Cheng Shieh et al 2015 Appl. Phys. Express 8 082101
InGaN-based light-emitting diodes (LEDs) with embedded conductive nanoporous GaN/undoped GaN (NP-GaN/u-GaN) distributed Bragg reflectors (DBRs) were demonstrated. Nanoporous GaN DBR structures were fabricated by pulsed 355 nm laser scribing and electrochemical etching processes. Heavily Si-doped n-type GaN:Si layers (n +-GaN) in an eight-period n +-GaN/u-GaN stack structure were transformed into a low-refractive-index, conductive nanoporous GaN structure. The measured center wavelength, peak reflectivity, and bandwidth of the nanoporous GaN DBR structure were 417 nm, 96.7%, and 34 nm, respectively. Resonance cavity modes of the photoluminescence spectra were observed in the treated LED structure with the nanoporous DBR structure.
Ikumi Yamada et al 2015 Appl. Phys. Express 8 066201
Silicon nanowires (SiNWs) have been grown on Si(100) substrates with and without a thermal oxide layer by rf magnetron sputtering of Si in Ar/H 2. In the experiments, thin Au layers were employed as catalysts, resulting in a significant and substantial growth of randomly oriented, polycrystalline SiNWs, typically 20 µm long and 350 nm in diameter after 60 min of growth on both Si and SiO 2 substrates at 700 °C. These indicate the possibility of providing an alternative method of SiNW growth that does not require toxic feed gases and high-temperature tube furnaces, and hence is suitable for growth on large-diameter substrates in industry.
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 42.65.Ky 42.60.Pk 42.15.Eq 07.57.Hm 42.60.Lh 42.65.Pc 42.30.Va 42.62.Cf 42.65.Tg 02.50.Fz 41.75.Fr 42.70.Hj 42.79.Fm 07.20.Dt 05.40.Ca 41.75.Jv 42.79.Bh 42.70.Mp 42.62.Be 42.30.Wb 42.25.Bs 33.50.Dq 07.60.Fs 42.50.Gy 07.55.-w 42.55.Rz 42.72.Bj 41.20.Jb 42.55.Wd 42.70.Qs 42.60.Jf 42.65.Re 42.70.Jk 31.15.ae 42.25.Ja 07.07.Df 31.15.ej 42.72.Ai 29.20.dg 42.25.Lc 31.15.A- 42.79.Gn 42.60.Da 42.79.Ci 29.25.Bx 07.85.Qe 42.55.Ye 42.50.Wk 42.50.Nn