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Talk:Isamu Akasaki

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This article seems to contain factual inaccuracies.

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Latest comment: 17 years ago4 comments1 person in discussion
  • According to the UC Berkeley website, blue LEDs were first fabricated in 1971 by Jacques Pankove, some 18 years before Akasaki's first success.
  • It also claims that Akasaki began working on blue LEDs in the late 1960s. Is there any evidence to support this?

At the moment, this article does not contain a single reference. If nobody can provide reliable sources to back it up, then it will have to be considered for deletion as original resarch. -- Sakurambo 桜ん坊 14:57, 23 January 2007 (UTC)Reply

Inadequate references

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Thanks, Miwaya, for adding those references. Unfortunately they don't seem to adequately back up the statements made in this article. For example, in the article, you claim that:

  • Isamu Akasaki is a Japanese scientist, best known for inventing p-n junction blue LEDs using gallium nitride (GaN) in as early as 1989, first in the world.

>> You can see world first LED figure at Fig 7 in this manuscript [1]. This LED was emitting blue light. Therefore, Isamu Akasaki and his group incent pn junction blue LED using GaN. —Preceding unsigned comment added by Miwaya (talk • contribs) 12:22, 24 January 2007 UTC

...and...

  • in 1985 he and his group succeeded,for the first time, in growing a high quality single crystal GaN on sapphire substrate by pioneering a low-temperature buffer layer technology. This high quality GaN enabled them to discover p-type GaN doping with magnesium (Mg) by MOVPE, to control n-type conductivity by silicon (Si) doping, and then to realize p-n junction blue LEDs in 1989, all first in the world., p-n junction blue/UV-LEDs

To back up these statements, you linked to an abstract of a research paper (dated October 6, 1989) which reads as follows:

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 ∼2·1016cm-3, the hole mobility is ∼8 cm2/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.

This paper doesn't support any of your claims. Akasaki was perhaps the first to report on the properties of the GaN p-n junction LED. That's all. Later on you claim that

  • He and his group achieved stimulated emission in the ultra-violet(UV)region with optical excitation from GaN at room-temperature in 1990 and stimulated emission by current injection from nitride-based quantum well diode at room-temperature in 1995,both for the first time in the world.

and you attempt to back up these claims by linking to another abstract (dated September 20, 1995) which reads as follows:

Quantum well structures composed of GaInN well and GaN barrier were fabricated. Room-temperature stimulated emission by pulsed current injection is observed from group III nitride using the very thin active layer, for the first time.

This abstract does not say anything about Akasaki being the first to achieve stimulated UV emission from GaN at room temperature. Finally, you claim that "Their inventions; high quality GaN, p-type doping, conductivity control of n-type nitrides , p-n junction LEDs and stimulated emission in the UV region by current injection are epoch-making and all other researches and developments of nitride-based blue/green/white LEDs, violet lasers, optoelectronic devices in the UV region and high-speed and high-power electronic devices are based on these inventions", and provide what appears to be a completely irrelevant link to the following abstract:

High-power device technology is a key technological factor for wireless communication, which is one of the information network infrastructures in the 21st century, as well as power electronics innovation, which contributes considerably to solving the energy saving problem in the future energy network. Widegap semiconductors, such as SiC and GaN, are strongly expected as high-power high-frequency devices and high-power switching devices owing to their material properties. In this paper, the present status and future prospect of these widegap semiconductor high-power devices are reviewed, in the context of applications in wireless communication and power electronics.

Please either find some better references or remove these claims from the article. In particular, your claim that he invented blue LEDs seems to be unsupportable. I would also like you to provide some explanation of the notability of this individual. For example, if he is so famous, why does he not yet have an article in the Japanese Wikipedia? -- Sakurambo 桜ん坊 11:42, 24 January 2007 (UTC)Reply

You can succeed by searching this word of "赤崎　勇" in Japanease Wikipedia. —Preceding unsigned comment added by Miwaya (talk • contribs) 12:35, 24 January 2007 UTC

I see. So you used the wrong character. -- Sakurambo 桜ん坊 13:48, 24 January 2007 (UTC)Reply

Moreover, I wrote a right reference —Preceding unsigned comment added by Miwaya (talk • contribs) 12:44, 24 January 2007 UTC

I have already given you the URL of a document at the UC Berkeley website which says that blue LEDs were first fabricated in 1971 by Jacques Pankove. Are you trying to tell me that this is not true? -- Sakurambo 桜ん坊 13:48, 24 January 2007 (UTC)Reply

No, the LED which Prof. Pankove fabricated was MIS structure, while LED which Akasaki fabricated was pn junction. In addition, as for the general marketed LED with pn junction. Morepver, "崎" and "﨑" are the same characters. But one is the chinese characters commonly used in Japan, and one is an old character.Because he seems to be an old character in family register, I worte using an old character in this page. —Preceding unsigned comment added by Miwaya (talk • contribs) 15:02, 24 January 2007 UTC

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