The Japanese Journal of Applied Physics (JJAP) is an international journal for the advancement and dissemination of knowledge in all fields of applied physics. The journal publishes articles dealing with the applications of physical principles as well as articles concerning the understanding of physics that have particular applications in mind. It 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.
Congratulations to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura on being awarded the 2014 Nobel Prize for Physics. Several of the key papers cited by the Nobel committee were published in this journal - visit the 2014 Nobel collection to read them for free.
From 2014, JJAP 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 JJAP Editorial Office at The Japan Society of Applied Physics. To submit a paper to JJAP, please connect to the editorial website.
JJAP publishes a number of Special Issues each year. These feature research articles presented at major international conferences. These articles are fully peer-reviewed to JJAP's usual acceptance criteria. Fifteen special issues are planned for 2014. Click here for a list of the 2014 Special Issues.
In the last 30 days
Hiroshi Amano et al 1989 Jpn. J. Appl. Phys. 28 L2112
Distinct p-type conduction is realized with Mg-doped GaN by the low-energy electron-beam irradiation (LEEBI) treatment, and the properties of the GaN p-n junction LED are reported for the first time. It was found that the LEEBI treatment drastically lowers the resistivity and remarkably enhances the PL efficiency of MOVPE-grown Mg-doped GaN. The Hall effect measurement of this Mg-doped GaN treated with LEEBI at room temperature showed that the hole concentration is ∼2·10 16cm -3, the hole mobility is ∼8 cm 2/V·s and the resistivity is ∼35 Ω·cm. The p-n junction LED using Mg-doped GaN treated with LEEBI as the p-type material showed strong near-band-edge emission due to the hole injection from the p-layer to the n-layer at room temperature.
Shuji Nakamura 1991 Jpn. J. Appl. Phys. 30 L1705
High-quality gallium nitride (GaN) film was obtained for the first time using a GaN buffer layer on a sapphire substrate. An optically flat and smooth surface was obtained over a two-inch sapphire substrate. Hall measurement was performed on GaN films grown with a GaN buffer layer as a function of the thickness of the GaN buffer layer. For the GaN film grown with a 200 Å-GaN buffer layer, the carrier concentration and Hall mobility were 4×10 16/cm 3 and 600 cm 2/V·s, respectively, at room temperature. The values became 8×10 15/cm 3 and 1500 cm 2/V·s at 77 K, respectively. These values of Hall mobility are the highest ever reported for GaN films. The Hall measurement shows that the optimum thickness of the GaN buffer layer is around 200 Å.
Shuji Nakamura et al 1991 Jpn. J. Appl. Phys. 30 L1998
High-power p-n junction blue-light-emitting diodes (LEDs) were fabricated using GaN films grown with GaN buffer layers. The external quantum efficiency was as high as 0.18%. Output power was almost 10 times higher than that of conventional 8-mcd SiC blue LEDs. The forward voltage was as low as 4 V at a forward current of 20 mA. This forward voltage is the lowest ever reported for GaN LEDs. The peak wavelength and the full width at half-maximum (FWHM) of GaN LEDs were 430 nm and 55 nm, respectively.
Kazuhito Hashimoto et al 2005 Jpn. J. Appl. Phys. 44 8269
Photocatalysis has recently become a common word and various products using photocatalytic functions have been commercialized. Among many candidates for photocatalysts, TiO 2 is almost the only material suitable for industrial use at present and also probably in the future. This is because TiO 2 has the most efficient photoactivity, the highest stability and the lowest cost. More significantly, it has been used as a white pigment from ancient times, and thus, its safety to humans and the environment is guaranteed by history. There are two types of photochemical reaction proceeding on a TiO 2 surface when irradiated with ultraviolet light. One includes the photo-induced redox reactions of adsorbed substances, and the other is the photo-induced hydrophilic conversion of TiO 2 itself. The former type has been known since the early part of the 20th century, but the latter was found only at the end of the century. The combination of these two functions has opened up various novel applications of TiO 2, particularly in the field of building materials. Here, we review the progress of the scientific research on TiO 2 photocatalysis as well as its industrial applications, and describe future prospects of this field mainly based on the present authors' work.
Shuji Nakamura et al 1992 Jpn. J. Appl. Phys. 31 L139
Low-resistivity p-type GaN films were obtained by N 2-ambient thermal annealing at temperatures above 700°C for the first time. Before thermal annealing, the resistivity of Mg-doped GaN films was approximately 1×10 6 Ω·cm. After thermal annealing at temperatures above 700°C, the resistivity, hole carrier concentration and hole mobility became 2 Ω·cm, 3×10 17/cm 3 and 10 cm 2/V·s, respectively. In photoluminescence measurements, the intensity of 750-nm deep-level emissions (DL emissions) sharply decreased upon thermal annealing at temperatures above 700°C, as did the change in resistivity, and 450-nm blue emissions showed maximum intensity at approximately 700°C of thermal annealing.
Shuji Nakamura et al 1993 Jpn. J. Appl. Phys. 32 L8
P-GaN/n-InGaN/n-GaN double-heterostructure (DH) blue-light-emitting diodes (LEDs) were fabricated successfully for the first time. The output power was 125 µW and the external quantum efficiency was as high as 0.22% at a forward current of 20 mA at room temperature. The peak wavelength and the full width at half-maximum (FWHM) of the electroluminescence (EL) were 440 nm and 180 meV, respectively. This value FWHM of was the smallest ever reported for blue GaN LEDs.
Shuji Nakamura et al 1992 Jpn. J. Appl. Phys. 31 1258
Low-resistivity p-type GaN films, which were obtained by N 2-ambient thermal annealing or low-energy electron-beam irradiation (LEEBI) treatment, showed a resistivity as high as 1×10 6 Ω·cm after NH 3-ambient thermal annealing at temperatures above 600°C. In the case of N 2-ambient thermal annealing at temperatures between room temperature and 1000°C, the low-resistivity p-type GaN films showed no change in resistivity, which was almost constant between 2 Ω·cm and 8 Ω·cm. These results indicate that atomic hydrogen produced by NH 3 dissociation at temperatures above 400°C is related to the hole compensation mechanism. A hydrogenation process whereby acceptor-H neutral complexes are formed in p-type GaN films was proposed. The formation of acceptor-H neutral complexes causes hole compensation, and deep-level and weak blue emissions in photoluminescence.
Tatsuya Shimoda and Takashi Masuda 2014 Jpn. J. Appl. Phys. 53 02BA01
We have been attempting to use liquid silicon (Si) in a solution process to develop semiconductor materials. We chose cyclopentasilane (CPS) as the raw material, which can be converted to poly(dihydrosilane) by photoinduced polymerization. Poly(dihydrosilane) is mixed with an organic solvent to form Si ink. We fabricated not only intrinsic Si ink but also both n- and p-type doped-Si inks. In the solution process, coating and pyrolysis are essential for device development. The parameters of these processes and the quality of the resultant solid film strongly depend on the properties and behavior of liquid Si, including those of CPS, poly(dihydrosilane), and Si ink. Here, we clarified the structure and properties of CPS, the photopolymerization of CPS, the structure of the polymer [poly(dihydrosilane)] in solution, the criteria for forming a uniform polymer film on a substrate, and the pyrolysis of a polymer film to an amorphous Si film. We also evaluated the properties of the resultant amorphous films. The quality of a solution-processed film was inferior to that of a vacuum-processed film just after the pyrolysis; however, it can be improved to a device-grade film by hydrogen radical treatment. So far, the devices that we have developed with liquid Si include polycrystalline Si thin-film transistors (TFTs), single-grained Si-TFTs, and thin-film solar cells. For TFTs, their excellent properties have been demonstrated. In this review article, we introduce the development of solar cells using hydrogenated amorphous Si (a-Si:H) films for the p–i–n structure. We also show that the solution-processed a-Si:H solar cells exhibit 0.31–0.51% efficiency under AM-1.5G (100 mW/cm 2) illumination.
Chihaya Adachi 2014 Jpn. J. Appl. Phys. 53 060101
Currently, organic light-emitting diodes (OLEDs) have reached the stage of commercialization, and there are intense efforts to use them in various applications from small- and medium-sized mobile devices to illumination equipment and large TV screens. In particular, phosphorescent materials have become core OLED materials as alternatives to the conventionally used fluorescent materials because devices made with phosphorescent materials exhibit excellent light-emitting performance. However, phosphorescent materials have several problems, such as their structure being limited to organic metal compounds containing rare metals, for example, Ir, Pt, and Os, and difficulty in realizing stable blue light emission, so the development of new materials is necessary. In this article, I will review next-generation OLEDs using a new light-emitting mechanism called thermally activated delayed fluorescence (TADF). Highly efficient TADF, which was difficult to realize with conventional technologies, has been achieved by optimizing molecular structures. This has led to the realization of ultimate next-generation OLEDs that are made of common organic compounds and can convert electricity to light at an internal quantum efficiency of nearly 100%.
Isamu Akasaki and Hiroshi Amano 2006 Jpn. J. Appl. Phys. 45 9001
Marked improvements in the crystalline quality of GaN enabled the production of GaN-based p–n junction blue-light-emitting and violet-laser diodes. These robust, energetically efficient devices have opened up a new frontier in optoelectronics. A new arena of wide-bandgap semiconductors has been developed due to marked improvements in the crystalline quality of nitrides. In this article, we review breakthroughs in the crystal growth and conductivity control of nitride semiconductors during the development of p–n junction blue-light-emitting devices. Recent progress mainly based on the present authors' work and future prospects of nitride semiconductors are also 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 42.70.Df 42.15.Eq 52.20.Fs 42.60.Lh 42.65.Pc 42.79.Ta 52.25.Jm 46.70.De 02.50.Fz 42.79.Sz 52.25.Fi 43.35.Pt 44.10.+i 52.40.Kh 42.79.Qx 52.38.-r 52.30.-q 42.55.Sa 42.70.Mp 52.50.-b 29.40.-n 52.35.Bj 42.25.Fx 52.35.Mw 42.60.Fc 32.60.+i 47.70.Pq 42.72.Bj 33.20.Fb 06.30.Dr 42.79.-e 42.65.Re 42.25.Kb 42.81.-i 42.40.-i 52.50.Jm 42.79.Dj 42.65.Hw 42.40.Kw 42.81.Pa 52.25.-b 42.79.Kr 52.25.Mq 42.79.Gn 42.60.Da 52.40.Fd 47.11.Fg 07.55.Ge 42.70.Gi