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蓝色发光GaN纳米晶和晶体的XAFS研究
람색발광GaN납미정화정체적XAFS연구
WT3HZ XAFS STUDIES ON LOCAL STRUCTURES OF NANOCRYSTALLINE AND

万方数据

红外与毫米波学报紅外與毫米波學報 홍외여호미파학보
JOURNAL OF INFRARED AND MILLIMETER WAVES
2001年 1期 7-10 ,共4页

张新夷%李忠瑞%闫文胜%王晓光%韦世强%陆坤权

장신이%리충서%염문성%왕효광%위세강%륙곤권

XAFS%蓝色发光GaN材料%局域结构. XAFS%藍色髮光GaN材料%跼域結構.
XAFS%람색발광GaN재료%국역결구.

利用XAFS(X-射线吸收精细结构)方法研究六方的纳米晶和晶体GaN在78K和300K温度下Ga原子的局域配位环境结构.对于第一近邻Ga-N配位,纳米晶GaN的平均键长R、配位数N、热无序度σT和结构无序度σS与晶体GaN的相近,分别为0.194nm、4.0、0.0052nm、0.0007nm;当温度从78K增加到300K,GaN样品中Ga-N配位的 σT增加不多,小于0.0005nm,表明第一近邻Ga-N配位的共价键作用力较强,几乎不受温度和晶体状态的影响.对于第二近邻Ga-Ga配位,R为0.318nm,纳米晶GaN的σS (0.0057nm)比晶体GaN的(0.001nm)大0.0047nm;在78K和300K时,纳米晶GaN样品的Ga-Ga配位的σT分别为0.0053nm和0.0085nm,这一结果表明Ga-Ga配位的σT受温度变化产生很大影响.纳米晶GaN中Ga原子的局域配位环境与晶体GaN的差别主要表现在第二近邻G a-Ga配位的σS相对较大,可能是由于纳米晶GaN内部缺陷及存在较多的表现不饱和配位原子所致.
이용XAFS(X-사선흡수정세결구)방법연구륙방적납미 정화정체GaN재78K화300K온도하Ga원자적국역배위배경결구.대우제일근린Ga-N배위,납미 정GaN적평균건장R、배위수N、열무서도σT화결구무서도σS여정체GaN적상근,분 별위0.194nm、4.0、0.0052nm、0.0007nm;당온도종78K증가도300K,GaN양품중Ga-N배위적 σT증가불다,소우0.0005nm,표명제일근린Ga-N배위적공개건작용력교강,궤호불 수온도화정체상태적영향.대우제이근린Ga-Ga배위,R위0.318nm,납미정GaN적σS (0.0057nm)비정체GaN적(0.001nm)대0.0047nm;재78K화300K시,납미정GaN양품적Ga-Ga배 위적σT분별위0.0053nm화0.0085nm,저일결과표명Ga-Ga배위적σT수온도변 화산생흔대영향.납미정GaN중Ga원자적국역배위배경여정체GaN적차별주요표현재제이근린G a-Ga배위적σS상대교대,가능시유우납미정GaN내부결함급존재교다적표현불포화배 위원자소치.
X-ray absorption fine structure (XAFS) was use d to investigate the local structures around Ga atoms in the hexagonal nanocryst alline and crystalline GaN under 78K and 300K. For the first nearest-neighbor c oordination of Ga-N, the average bond length R, coordination N, thermal disorder σT and structural disorder σS of nanocrystalline GaN ar e similar to those of crystalline GaN, which are 0.194nm, 4.0,0.0052nm and 0.000 7nm, respectively. When the temperature is elevated from 78K to 300K, the σ T in GaN samples increases by lower than 0.0005nm. It indicates that the Ga- N covalent bond is much stronger, and is nearly independent of temperature and c rystalline state. For the second nearest-neighbor Ga-Ga coordination, the R values of the samples are about 0.318nm; the σS(0.0057nm) of nanocryst alline GaN is 0.0047nm larger than that of crystalline GaN(0.001nm); the σT of Ga-Ga coordination in nanocrystalline GaN are 0.0053nm, 0.0085nm for the temperature of 78K and 300K, respectively. This shows that the σT of Ga- Ga coordination is greatly affected by the temperature. The major difference of local structure around Ga atoms between nanocrystalline GaN and crystalline GaN is shown by the relatively large σS of the Ga-Ga second nearest-neighbo r shell in nanocrystalline GaN. The reason may be explained by that there exist larger defects and unsaturated surface atoms in nanocrystalline GaN.