Hiroshi Amano, Nobel Prize in Physics 2014: Nobel Lecture

Summary

Professor Amano, born in 1960, shares his journey in developing gallium nitride-based blue LEDs, which revolutionized display technology. His research at Nagoya University led to the invention of high-quality gallium nitride films and P-type gallium nitride, overcoming significant challenges. Amano emphasizes the impact of LEDs on energy savings and encourages young researchers to tackle difficult subjects for societal improvement. His work has profound implications for lighting and displays, contributing to energy efficiency and accessibility.

Takeaways

• 🎓 Professor Amano, born in 1960 in Japan, received his PhD from Nagoya University in 1989 and is currently a professor there.
• 🌟 He expressed gratitude to the Nobel Committee and the Swedish Academy of Science for the recognition of his work.
• 🔬 His lecture focused on two main topics: the growth of gallium nitride on sapphire substrates and the development of p-type gallium nitride.
• 💡 The significance of blue LEDs was highlighted, emphasizing their impact on modern displays and electronics, such as portable games and smartphones.
• 📈 The 'H Haitz' graph illustrated the exponential improvement in LED performance over time, similar to Moore's Law in silicon-based technology.
• 🧪 The challenges in growing gallium nitride included high pressure and temperature requirements, similar to those for synthesizing diamonds.
• 🔍 Amano's early research involved over 1,500 attempts to grow high-quality gallium nitride films, facing significant difficulties due to lattice mismatch issues.
• 🏆 A breakthrough came with the discovery of the low-temperature buffer layer technique, which allowed for the successful growth of gallium nitride.
• 🌐 The invention of p-type gallium nitride was a critical step, enabling the creation of blue LEDs and contributing to energy-efficient lighting solutions.
• 🌿 The potential of LED technology to save energy and provide lighting in areas without electricity was discussed, with a focus on its benefits for future generations.

Q & A

What significant invention did Professor Amano contribute to that changed the world of lighting?

Professor Amano contributed to the invention and development of blue LEDs using gallium nitride, which revolutionized the world of lighting and enabled the creation of white LEDs for more efficient lighting.

What was the major challenge faced by Professor Amano and his team in the early stages of their research on gallium nitride?

The major challenge was growing high-quality gallium nitride due to the need for high pressure and high temperature, similar to the synthesis of diamonds, and the difficulty in finding a suitable substrate material that does not react heavily with ammonia.

What is the 'H Haitz' law mentioned in the script, and how does it relate to LED performance?

The 'H Haitz' law refers to the improvement of LED performance by a factor of 20 per decade since the invention of commercially available red LEDs. This improvement is similar to Moore's law in silicon-based LSI and signifies the rapid advancement in LED technology.

What is the significance of the 'low temperature buffer' technology developed by Professor Amano?

The 'low temperature buffer' technology is significant because it allowed for the growth of high-quality gallium nitride films, which was a crucial step in achieving high-performance blue LEDs and was adopted by many researchers worldwide.

Why was achieving p-type gallium nitride a critical milestone in the development of blue LEDs?

Achieving p-type gallium nitride was critical because it allowed for the creation of a p-n junction necessary for the efficient operation of LEDs, enabling them to emit bright blue light, which was previously difficult to achieve.

What was the role of magnesium in the development of p-type gallium nitride?

Magnesium played a crucial role as it was found to be much more effective than zinc in activating acceptors in gallium nitride, leading to the successful creation of p-type gallium nitride, which was essential for the development of blue LEDs.

How did the indium gallium nitride LEDs contribute to energy savings, as mentioned in the script?

Indium gallium nitride LEDs contributed to energy savings by replacing traditional lighting with more energy-efficient LED lighting, which can save a significant amount of electricity, as demonstrated by the potential to replace 70% of lighting with LEDs by 2020 in Japan.

What was the impact of the 2011 Great East Japan Earthquake on Japan's energy generation, and how did LEDs play a role in addressing it?

The 2011 Great East Japan Earthquake led to the shutdown of nuclear power plants, which supplied 30% of Japan's electricity. LEDs played a role in addressing the energy shortfall by providing more energy-efficient lighting solutions, contributing to energy savings and helping to adapt to the reduced electricity generation.

What message does Professor Amano have for young researchers based on his experiences in developing LEDs?

Professor Amano encourages young researchers to tackle more difficult subjects and contribute to the improvement of human lifestyles, emphasizing that the current facilities and funding are much better than in the past, providing more opportunities for innovation.

What was the age of Professor Amano when he achieved the breakthroughs in low temperature buffer and p-type gallium nitride?

Professor Amano was 24 years old when he achieved the low temperature buffer and 28 years old when he achieved p-type gallium nitride.

Outlines

00:00

🎓 Introduction and Background of Professor Amano

Professor Amano, born in 1960 in Hamamatsu, Japan, received his PhD from Nagoya University in 1989 and is currently a professor there. He expresses his gratitude to the Nobel Committee and the Swedish Academy of Science for the opportunity to present. He introduces two topics: the growth of gallium nitride on sapphire substrates and the development of p-type gallium nitride. He aims to discuss these achievements from a young researcher's perspective and shares his personal journey, including his early interest in blue LEDs and the impact of their development on modern displays and devices.

05:02

🔬 Challenges in Growing Gallium Nitride

The paragraph discusses the technical challenges faced in growing gallium nitride. It requires high pressure and high temperature similar to diamond synthesis. The search for a suitable substrate led to the selection of sapphire due to its chemical stability with ammonia. However, the large lattice mismatch of 16% between gallium nitride and sapphire posed a significant hurdle. The paragraph also touches on the history of LED development, the 'H Haitz' law, and the initial difficulties in achieving p-type conductivity in gallium nitride LEDs. It highlights the resourcefulness of the research team in developing their own growth reactor and the numerous failed attempts at growing high-quality gallium nitride films.

10:02

🏆 Breakthrough in Gallium Nitride Growth

This paragraph details the breakthrough achieved by the speaker in growing gallium nitride. The speaker experimented with aluminum nitrate as a nucleation center for gallium nitride growth, leading to the successful creation of highly crystalline gallium nitride films. This technique, known as the low-temperature buffer layer, was a significant advancement and has been adopted by researchers worldwide. The paragraph also discusses the speaker's continued efforts to achieve p-type gallium nitride, which was a critical step towards the development of blue LEDs.

15:05

📚 The Quest for P-Type Gallium Nitride

The speaker recounts his research on p-type gallium nitride, which was a challenging and elusive goal. After unsuccessful attempts with zinc doping, the speaker turned to magnesium doping based on theoretical predictions and previous research. The paragraph describes the successful achievement of p-type conductivity in gallium nitride using magnesium, which was confirmed through various measurements. It also mentions the work of other researchers, including Nakamura's claim of achieving p-type gallium nitride through a simpler method involving thermal annealing.

20:07

🌐 Impact of Indium Gallium Nitride LEDs on Energy Efficiency

The paragraph highlights the energy-saving potential of indium gallium nitride LEDs, especially in the context of the 2011 earthquake in Japan that led to a significant reduction in nuclear power generation. The speaker discusses the predicted replacement of traditional lighting with LEDs, which could save a substantial amount of energy. The paragraph also touches on the integration of LED lighting with solar cells and batteries to provide sustainable lighting solutions, particularly for areas without access to electricity. The speaker concludes with a message to young researchers, encouraging them to tackle difficult subjects for the betterment of human life.

25:08

🙌 Acknowledgments and Closing Remarks

In the final paragraph, the speaker expresses his gratitude to various institutions, including Nagoya University and the research facilities that supported his work. He also acknowledges his family for their continuous support. The paragraph concludes with the speaker's thanks for the audience's attention, followed by the end of the presentation.

Keywords

💡Gallium nitride

Gallium nitride (GaN) is a compound of gallium and nitrogen, which is a semiconductor material used in light-emitting diodes (LEDs) and other electronic devices. In the video, GaN is central to the discussion of LED development, particularly in the creation of blue LEDs, which were a significant breakthrough in display technology. The script mentions the difficulty in growing high-quality GaN films, which was a major challenge overcome by the researchers.

💡LEDs

Light-emitting diodes (LEDs) are semiconductor devices that emit light when an electric current passes through them. The video discusses the evolution of LEDs, especially the development of blue LEDs using GaN, which enabled full-color displays and significantly improved the efficiency and brightness of lighting technologies. The script provides historical context, such as the commercialization of red LEDs and the subsequent development of other colors.

💡High pressure and high temperature

These terms refer to the conditions necessary for the synthesis of certain materials like GaN. The video explains that growing GaN requires conditions similar to those used in diamond synthesis, indicating the technological challenges involved. The script mentions the need for high pressure and temperature as a hurdle that researchers had to overcome to develop GaN-based LEDs.

💡Low temperature buffer

The low temperature buffer is a technique mentioned in the video that allowed for the successful growth of high-quality GaN films. This innovation was crucial for the development of blue LEDs and is an example of the practical solutions found by researchers to overcome the material's growth challenges. The script describes how this technique was used to improve the surface morphology of GaN layers.

💡P-type semiconductor

In the context of semiconductors, 'P-type' refers to a material doped with impurities that create an excess of positive charge carriers, known as holes. The video discusses the challenge of achieving P-type conductivity in GaN, which was essential for creating efficient blue LEDs. The script details the research efforts and eventual success in developing P-type GaN, a key milestone in LED technology.

💡Lattice mismatch

Lattice mismatch refers to the difference in the crystal structures of two materials when they are combined. In the video, the large lattice mismatch between GaN and the sapphire substrate was a significant obstacle to overcome. The script explains how researchers addressed this issue, which was critical for the successful growth of GaN layers on sapphire substrates.

💡Indium gallium nitride

Indium gallium nitride (InGaN) is a ternary compound semiconductor used in the creation of LEDs with varying colors, including blue. The video discusses the challenges in growing InGaN with a high indium content, which is necessary for achieving blue light emission. The script mentions the breakthrough in growing InGaN with a high enough indium content to enable blue light emission, contributing to the development of modern LEDs.

💡Quantum well

A quantum well is a semiconductor structure that confines electrons in two dimensions, leading to quantized energy levels. The video mentions the use of quantum well structures in improving the efficiency of LEDs. The script refers to the development of quantum well-based structures as an important step in enhancing LED performance, particularly in terms of light output and energy savings.

💡Energy savings

The term 'energy savings' in the video refers to the reduction in energy consumption achieved through the use of more efficient lighting technologies, such as LEDs. The script provides an example of how LED lighting can contribute to energy savings, especially when combined with renewable energy sources like solar cells, and the potential impact on reducing overall electricity consumption.

💡Young researchers

Throughout the video, there is an emphasis on the role and potential of young researchers in driving scientific advancements. The script includes a message to the younger generation, encouraging them to tackle difficult subjects and contribute to improving human lifestyles through research and innovation, reflecting the importance of nurturing the next generation of scientists and engineers.

Highlights

Professor Amano was born in 1960 in Hamamatsu, Japan, and received his PhD from Nagoya University in 1989.

He presents on the growth of gallium nitride and P-type gallium nitride.

The majority of his presentation overlaps with the previous presenter, Professor Isamu Akasaki.

Amano emphasizes the impact of blue LEDs on portable games and smartphones.

He discusses the historical development of LEDs, starting with red LEDs in the 1960s.

The performance of LEDs improved by a factor of 20 per decade, known as the Haitz's law.

Professor Shuji Nakamura developed the first blue LEDs using gallium nitride in 1971.

Amano joined Akasaki's group in 1982 as an undergraduate student, aiming to develop blue LEDs.

The difficulty of growing gallium nitride lies in the need for high pressure and high temperature.

Sapphire was identified as a promising substrate due to its chemical stability with ammonia.

Amano and his team faced challenges with the large lattice mismatch between sapphire and gallium nitride.

They developed a low-temperature buffer technology to improve the growth of gallium nitride.

Amano's research focused on achieving P-type gallium nitride from 1985 to 1988.

They successfully achieved P-type gallium nitride using magnesium doping.

The development of blue LEDs led to energy savings, especially after the 2011 earthquake in Japan.

Amano encourages young researchers to tackle difficult subjects for the improvement of human lifestyle.

He acknowledges the support from Nagoya University, major universities, and his family.

Transcripts

uh Professor Amano uh was born in 1960

in hamamatsu in Japan uh he got his PhD

in

1989 uh from Nagoya University and

that's also where he's now a professor

so please uh enter the stage and and and

give the the second

[Applause]

lecture um good morning U ladies and

gentlemen I still can not believe that

I'm here and presenting the Noel rures

so first of all uh I'd like to give

sincere thanks to the lawyer Swedish

Academy of

Science uh today uh I'd like to present

two topics one is the growth of gum

nitride on the supply substrate and the

second is the P typee gum

nitrate uh majority of my presentation

overlaps that the uh the previous

presenter PR isama akasaki but I'd like

to explain this achievement from The

Young researchers point of view so um at

the end of my presentation I'd like to

send a message to the young

Generations

first I'd like to give uh the example

how BR is changes our lives for young

Generations

maybe most

familiar uh

items uh would be um portable

games and also the seral phones on or

the

smartphones the first uh portable games

were commercialized in

1976 and the first uh C phon

were available in

1989 but until 1990s at the end of

1990s uh all the displays are

monochrome so the young Generations I'd

like to emphasize that you can enjoy the

huruka dis phrase by the emergence of

the Brew eles okay

uh this is the very famous biograph

showing the Improvement of the

performance of the

LEDs press uh H this was uh written by

uh Dr height the retired us

scientist in

1962 uh us uh Professor uh nickak uh

invented and developed the commercially

available red LEDs using the gum maride

post

fite and since then the performance of

LEDs improved by a factor of 20 per

decad so this Improvement is called the

height low which is similar to the mo

was

low uh in case of uh silicon based LSi

and since after the Leed LEDs uh yellow

LEDs and green LEDs have been also

commercialized and as for the blue

LEDs in

1971 Professor Jack pankov uh developed

the gum nitrite based LEDs but it was

mis type LED so it was not

commercialized

I started the natural research at

1982 after the 14 years of the research

and experiments Professor akasaki moved

from the company to the Nago University

in

1981 and I joined his group in

1982 uh as an undergrad

student the reason why I choose uh uh

his laboratory is because the gradation

research

subject nitrate based blue LEDs are so

simple and so

fascinating uh at that time I thought

that the size of the TV system based on

Brown tube was so

Barky so if I could achieve blue

LEDs I could change the World by

shrinking the size of the

display at that time I was not aware

that this subject was so difficult I

thought it was maybe it's it's

easy the reason why I'd like to explain

why it was so difficult to grow gum

nitrate if you want to grow life siiz B

gum nitrate you need a high pressure and

high temperature which is the similar to

the synthesis of the diamond or even

higher so you need to uh use uh chemical

reaction to reduce the pressure and the

temperature in addition you need um

falling

substrate for theal growth of gum

nitrate um but

the

ammonia the nitrogen nitrogen source is

so reactive at high temperature so the

candidate of the substitute material is

very very

limited the saire is one of the most

promising substrate because it does not

react with ammonia so

heavily but the most serious problem of

The Sire was the large latest mismatch

of

16% in general the lest M mismatch for

the hopx growth should be less than

1% so the 16% R mismatch is almost

impossible to grow gum

nitrate uh press

pankov developed in 197

1 the Mis type gum nitrate using the

hydride VAP taxi using the metal gum

hydrogen chloride and

ammonia but uh they could not achieve

the P type gum nitrate so efficiency is

limited to be

low also another problem of the

difficulty in achieving the uh bright

blue emission was related to the

sensitivity of human

eye responsibility of the blue P blue

right is only

3% compared with

the uh Irish green

555 nanometer emission uh

right so uh

uh the the

students tried to start the research of

the gum nitrate growth by metal organic

V pH F

taxi at that time the funding situation

of the university in Japan in mid 80s is

not so sufficient so uh the students

have to develop the ch grow reactor by

ourselves headed by Dr

K but this that situation is very happy

or very good for us because we can

manage the config regulation by

ourselves uh I have tried more than

1,500 Times by changing the growth

conditions such as gross temperature

grow uh FL rate and line achiev

configuration and the Sor shape and so

on and so on but UNS unsuccessful I

could not get high quality G nro film

for me the large ltis mismatch was too

great to overcome so almost two years

passed without success

in

February uh year

2085 that was my almost the final month

of my H Master

course uh at that time only one foreign

student and I decided to start the PHD

program the next

April and while other Japanese students

enjoyed the graduation

trip

I uh carried out the very lonely

experiments

okay

uh Dr K uh one year older uh student uh

focused on the growth of aluminium gum

nitrate while I focused on the growth of

gum

nitrate if we compare the surface

morphologies of these two materials his

aluminum gum nitrate seems to be better

than my gum

nitrate so uh I thought that the

aluminum containing material or even

aluminum nitrate is important to improve

the surface moror

so I decided to use the aluminum nitrite

before the growth of gum

nitrite but I knew that the substrate

temperature should be higher than 1200

Cate for the architectural growth of

aluminum nitrate but as I mentioned we

used the very old system old oscillator

so it did not work well even though I

managed to

control and just at that time I

remembered the hint during discussion in

the

laboratory Dr

saaki uh the associate pressor mentioned

that in case of G uh Bon fori on cityon

growth the latest mismatch of which is

as large as 24 per pereral of

phosphorous gas is very effective to

improve the surface M ory and he claimed

that phosphorus atom act as the

nucleation Center so I imagined that the

low temperature deposition of aluminum

nitrate and very tiny aluminum nitrate

should act as the nucleation Center

then I proceeded the gum nitrite

growth so when I took the sample out

from the

reactor it was almost the same as the

safire

substrate perfectly frat and perfectly

transparent

so I my first impression was oh I forget

to supply the G

trianium but when I checked the all the

bars I found that I operated properly so

I checked uh the sample by nari type

Optical microscope and found that we

achieved the highly

ER frat gum nitride for the first time

and following the the suggestion of

Professor akasaki I checked the crant

quality electrionic properties Optical

properties and found that all the

properties were Superior to uh the

previous reports so this technology is

called the low temperature buffer and uh

can be used by many researchers

worldwide

like

this then the of course our next Target

is to realize uh P type gum

nitrate from 1985 to

1988 I concentrated on growing the zinc

do gum nitrate but all the samples shows

highly legislative or end type

when I measured the luminescence what

luminescence at cryogenic temperature I

observed the very narrow uh excitonic

Peak so I was excited and tried to

present at the Japan Society for Applied

Physics annual meeting held at nag

University

and when I enter the loom I was

surprised that only four people

including prakas German I were in the

loop at that time uh majority of the

researchers were interested in the zinc

selenide or zinc suide the N uh the

researches of the nitr are quite

minority also uh I observed the this uh

phenomena that during the cathod

luminesence measurement of zinc do gum

nitrate the blue luminesence was

irreversibly enhanced so I call it the

low energy Electron Beam irradiation the

re treatment for short uh but even after

the re treatment the zinc do gum nitrate

did not show the P type

conduction in

1989 I became the research

associate of the uh press akasaki ra now

University and when I read the book The

bondes and band in semiconductor written

by JC

Phillips uh I saw this graph very very

appealing this graph clearly shows that

in case of gum

phosphide magnesium is much much better

than zinc in terms of the activation of

acceptor as for the Magnesium I I should

commment that press marusa at that time

the Stanford University

student uh developed the world's first

pilot but Mis type LEDs uh using the

magnet magnes gum

nitrate okay

uh we the docto at that time Master Co

student and I grew plenty of magnesium

do gum nitrate

uh the

ASR uh m g shows highly legis but after

the re

treatment

uh Dr uh Kito said the some sample shows

P type

Behavior but I knew that the uh by hoto

Pro measurement I knew that the hot prob

measurement is not so reliable so even

though we

presented maybe no one can believe the P

type conduction so uh he measured the

whole effect measurement and finally we

recognize that we have achieved the P

typ gum nitrate for the first

time um in

1992 pres Nakamura claimed that uh

they can he he can realize the P type G

nitr even by much simpler method that is

theral analing in

1992 okay the mechanism is shown

here the ASR sample was uh the Magnesium

was participated by

hydrogen so the re treatment or the Thon

aling is uh effective to dissolve the

hydrogen from the passivated

Magnesium

okay uh which was first explained by

Professor Fon in

1992

okay we are still have the problems of

uh Brew

emission the band gap of gum nitrite was

is in the UV Le

for the blue emission we need to grow

the Indian containing roids Indian Gum

nitrate of course we have tried uh to

grow the indium gum

nitrate but uh it is also very very

difficult so uh we grew indium gum

nitrate with the indium content less

than 3% which is uh the band Gap is

still in the UB

religion in

1989 Dr matoka NT succeeded in growing

the blue reminisence indium calium

nitrate by growing it at very very high

ammonia flate condition and also in

nitrogen carrier gas

atmosphere so uh combining the high

quality uh Crystal technology P type G

nitrate technology and the the structure

of indium gum nitr and gum nitrite

Professor nak team first succeeded the

commercialization of nitrate based

Brewer in

1993 and also his group realized the

quantum well based structure in

1995 which is also very important for

the Improvement of the efficiency of uh

r is maybe he will explain uh in the

next uh

presentation okay let me explain how the

indium gum nitrite LS contribute to the

Energy

savings maybe you remember

that the Great Earthquake attacked East

Japan in year

2011 before

2011

uh nuclear power plant supplied the 30%

30% of the total elect uh electricity

generation in Japan but now none of the

48 reactors were operated

now every reactor

was uh not operated

so we have to find the

solution for

adapting these

30% uh

eloris some research company in Japan uh

predicted that by year

2020 More than

70% of the

writing is replaced to L writings by

which uh we can save about 7% of the

total energy consumption by year 20

2020 more

importantly by combining the LED

lightings with solar cells and

batteries we can supply

the very simple writing system

especially to the Young Generation or

children uh who cannot be access to the

electricity so we can supply ER the

lightings so children can read the book

or study even at night

okay uh this is the message to the young

researchers when we realized the low

temperature buffer I was only 24 years

old and when we realized the P type

Gallum nitrate I was

28 years

old of course I was very very lucky

that I can carried out the research

under the excellent supervision of pram

akasaki and the distinguished

K but these

days the

facilities and funding should be much

much better than year

208s

so I'd like to see that the younger

generation try and Tackle

more uh the

more difficult

subject for the

contribution of the Improvement of a

mankind life uh

style okay I'd like to acknowledge uh

this thing

uh

cores n University major university and

N

university the the go to the center

research and laboratory uban

nxo and finally I'd like to

acknowledge my

family uh for continuous support thank

you so much for your kind of attention

[Music]

[Applause]