ISAJ Newsletter - Volume 6, Issue 1 (March 2021)

From the Editor’s Desk

Greetings and a warm welcome to the first issue of ISAJ Newsletter in 2021! We take this opportunity to wish you a healthy and productive life in 2021 and hope that you are taking all necessary precautions amid COVID-19 pandemic.

In this issue, we present you with two research articles and one event report on 11th Annual ISAJ Symposium-2020. The research articles are on the study of low-temperature growth of III-Nitride materials by radical-enhanced metalorganic chemical vapor deposition and on Augmented Reality and its future prospects. This issue also contains pictures of our 11th annual symposium held last year.

ISAJ organized its 11th Annual Symposium on December 4th, 2020, using Zoom platform. The symposium theme was “Innovations in Science and Technology for New Issues and Challenges”. It had a special interest session on COVID-19. There were around 100 participants, including 8 plenary speakers, 26 invited speakers and 24 student presenters.

Research Spotlight: Low-Temperature Growth of III-Nitride Materials by REMOCVD

By Dr. Frank Wilson Amalraj, Nagoya University

Introduction

III-nitride semiconductors are attractive for optical and electronic device applications such as light emitting diodes (LEDs), laser diodes (LDs), and high electron mobility transistors (HEMTs). The band gaps of III-nitrides are large and direct:

• InN: 0.7 eV
• GaN: 3.39 eV
• AlN: 6.2 eV

Band gaps from 0.7 eV to 6.2 eV can be obtained by suitable combinations in the AlGaInN system spanning the UV and visible ranges.

Challenges with Conventional MOCVD

GaN epitaxial layers grown on Si substrates by metal organic chemical vapor deposition (MOCVD) have several disadvantages:

1. High V/III ratio: Several thousands, with ammonia consumption accounting for nearly half of production cost
2. High temperature: Above 1000°C causing GaN decomposition and increased TMG consumption
3. InN growth difficulty: High temperature prevents effective In-containing nitride growth
4. Wafer issues: Breakage and bowing on large diameter substrates due to high temperature

Novel REMOCVD Solution

At Nagoya University, we developed the radical-enhanced MOCVD (REMOCVD) method using VHF (very high frequency) plasma to decrease growth temperature:

Key Features:

• Uses 100 MHz VHF plasma
• No ammonia gas required
• Growth temperature reduced to 800°C (from >1000°C)
• Remote plasma configuration prevents TMG cracking

Optical Emission Spectroscopy Results

The plasma provides various reactive nitrogen species:

• Grounded N atom (⁴Sº)
• Metastable N atom (²Dº, ²Pº)
• Electronically excited N₂ molecules (A³Σᵤ⁺)

Small amounts of ammonia species generated in the N₂ and H₂ plasma are sufficient for GaN growth.

Growth Results

Homoepitaxial GaN grown at 800°C showed:

• Crystal quality: XRC-FWHM of 100 arcsec
• Surface morphology: Smooth surfaces confirmed by SEM and AFM
• Interface: Eliminated roughness through N₂/H₂ plasma cleaning
• Cross-sectional TEM: High-quality epitaxial layers

This novel method is promising for replacing conventional MOCVD from the viewpoint of production cost and device performance.

Idea Brewing: Augmented Reality Industry and Online Streaming Platforms Are On a Collision Course

By Srikant Manas Kala, Osaka University

The AR Revolution

Augmented Reality (AR), unlike its completely immersive comrade Virtual Reality (VR), is poised to be a mobile paradigm. AR blends the real with the virtual on the go and enhances our view of reality.

AR Requirements:

1. Live video of the real world
2. Processing power to analyze objects
3. Knowledge database for enhancement
4. Computational power for rendering

Example: Watching a game in a stadium, an AR app can detect players, look up their stats, and display information on your view of the live game.

The Upload-Download Asymmetry

We are voracious consumers of digital media. Between 2012 and 2017, global mobile data consumption increased 17 times, and by 2022 it will further increase 7 times. We will consume 930 exabytes of video data in 2022.

Current Network Strategy:

• Bandwidth split favors downloads
• Upload speeds are generally slow
• This asymmetry benefits streaming services
• Creates self-propelling cycle of video consumption

The AR Conundrum

AR is inherently upload-intensive and demands the current asymmetry be reversed:

• Camera field view: 60-70 degrees
• Data transfer needed: 10 Gb per second (theoretical)
• Compressed 4K video: 20-30 Mb/s (practical)
• Average US upload speed: 9.75 Mb/s (insufficient)

5G Promise and Limitations

5G offers:

• Download speeds up to 300 Mb/s
• Upload speeds up to 50 Mb/s
• High mobility service up to 100 kmph

Yet it’s still short of bandwidth required for flawless AR experience.

A Data War is Imminent

Global AR/VR data traffic is expected to grow 12-fold from 22 petabytes per month in 2017 to 254 petabytes per month in 2022.

The Conflict:

• AR industry needs upload-heavy bandwidth allocation
• Streaming platforms want to maintain download-heavy asymmetry
• End users will ultimately decide: “Netflix” or “Pokemon Go”

“For now, we just wait and watch and let it play out. Pun intended.”

Event Report: 11th ISAJ Annual Symposium 2020 (Virtual)

The 11th annual ISAJ Symposium “Innovations in Science and Technology for New Issues and Challenges” was held virtually on December 4, 2020, using Zoom platform and live-streamed on YouTube.

Opening Session

• Welcome Address: Dr. Sunil Kaul, Chairman ISAJ
• Inaugural Address: H.E. Mr. Sanjay Kumar Verma, Ambassador of India to Japan (pre-recorded)
  • Emphasized India-Japan ICT collaboration
  • India as software powerhouse, Japan as hardware leader
• Keynote Lecture: Prof. Masaru Hori, Director cLPS, Nagoya University
  • Plasma sciences in medicine and agriculture
  • Future plasma processes towards SDGs

Special COVID-19 Session

Featured talks on:

• Immunological mechanisms
• SARS-CoV-2 genetics
• Role of Ashwagandha in human health
• Psychological effects on mental health
• Rise of AI in societal transformation

Parallel Sessions (First Time)

1. Industrial and Technological Innovations
2. Human Health and Safety
3. Energy and Environment

Participation

• 8 plenary talks
• 26 invited talks
• 24 student oral presentations
• 100+ participants from Japan and beyond
• 16 young researchers in organizing committee

Best Presentation Awards

Human Health and Safety:

• Mr. Ashish Kaul (AIST, Tsukuba)
• Mr. Ahmed Elwakeel (AIST, Tsukuba)

Energy and Environment:

• Mr. Hitesh Supe (Hokkaido University)
• Ms. Manpreet Kaur (NIMS, Tsukuba)

Industrial and Technological Innovations:

• Mr. Hannibal Paul (Ritsumeikan University)
• Mr. Raghav Soni (Osaka University)

Virtual Format Success

Organizing the symposium virtually allowed reaching a broader audience countrywide in Japan and having participants from beyond Japan, marking a successful adaptation to pandemic circumstances.