さきがけ 研究者

研究課題名

高効率光電変換デバイスの実現に向けたⅢ族窒化物のマルチバンドエンジニアリング

プロフィール

SANG Liwen
桑 立雯
SANG Liwen
サン リウエン

物質・材料研究機構
国際ナノアーキテクトニクス研究拠点(MANA)
独立研究者

1984年 中国山東省生まれ
2010年 北京大学 博士課程修了、博士(理学)
2010年 物質・材料研究機構 ポスドク研究員
2012年 物質・材料研究機構 ICYS-MANA若手研究員
2014年 物質・材料研究機構 MANA独立研究者

研究分野:窒化物薄膜成長、光電デバイス

  • ※プロフィールは、終了時点のものです。

研究内容紹介

In recent years, due to the dwindling fossil fuels and a series of environmental issues resulted from fossil fuels, the development of a new kind of clean and high-efficiency photo · electricity energy conversion technology is in great need. Solid-state lighting has the potential to reduce lighting energy usage by nearly one half and contribute significantly to the world climate change solutions. Solar photovoltaic power generation is regarded as the most reliable and continuable power generation technology. However, the current photo to electricity and electricity to photo conversion efficiencies of existing photonic and electronic devices are far from their ideality. For example, in the photovoltaic field, due to the lattice mismatch and current mismatch, it is difficult to achieve the full solar spectrum absorption even multi-junction structures are utilized. Therefore, solar cells using Si, CuInGaSe, or GaAs-based materials are all concentrated on the long-wavelength absorption (<2eV), which makes the conversion efficiency unable to improve. On the other hand, three-primary color (RGB) mixing is considered to be the most efficient method for generating high-brightness white light illumination in the solid-state light field. But, RGB can not be realized by using one material system, which greatly increases the cost and leads to unnecessary efficiency loss during integration.
 Ⅲ-Nitride semiconductor family (GaN, InN, AlN and their ternary and quarternary alloys) exhibit the widest direct bandgaps among all the semiconductors, from near infrared (InN at 0.65eV) to the deep ultraviolet (AlN at 6.2eV), which cover almost all the spectrum This unique property makes the possibility of full-color emitting and absorption photonic devices using one material system, which will greatly improve the efficiency and reduce cost. However, as a result of the high n-type background conductivity and strong surface electron accumulation, p-type doping in In-rich InxGa1-xN remains a worldwide puzzle, which hinders the development of long-wavelength absorption and emitting devices.
 The objective of this research is to solve the chanllenging problem in Ⅲ-Nitride field of p-type doping in In-rich InxGa1-xN by using multi-band nano-interface control. To demonstrate this novel concept, we will try to develop high-efficiency photo · electricity energy conversion devices, including ultra-high conversion efficiency solar cells and long-wavelength red light emitting diodes by using In-rich InxGa1-xN p-n junction structures.

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