CAJ | 학술논문

利用拉曼散射技术对N型4H-SiC单晶材料进行了30～300 K温度范围的光谱测量。实验结果表明，随着温度的升高，N型4 H-S iC单晶材料的拉曼峰峰位向低波数方向移动，峰宽逐渐增宽。分析认为，晶格振动随着温度的升高而随之加剧，其振动恢复力会逐渐减小，使振动频率降低；原子相对运动会随温度的升高而加剧，使得原子之间及晶胞之间的相互作用减弱，致使声学模和光学模皆出现红移现象。随着温度的升高，峰宽逐渐增宽。这是由于随着温度的升高声子数逐渐增加，增加的声子进一步增加了散射概率，从而降低了声子的平均寿命，而声子的平均寿命与峰宽成反比，因此随着温度的升高峰宽逐渐增宽。声子模强度随温度升高呈现不同规律，E2（LA），E2（TA），E1（TA）和A1（LA）声子模随着温度升高强度单调增加，而E2（TO），E1（TO）和A1（LO）声子模强度出现了先增后减的明显变化，在138 K强度出现极大值。分析认为造成原因是由于当温度高于138 K时，高能量的声子分裂成多个具有更低能量的声子所致。
이용랍만산사기술대N형4H-SiC단정재료진행료30～300 K온도범위적광보측량。실험결과표명，수착온도적승고，N형4 H-S iC단정재료적랍만봉봉위향저파수방향이동，봉관축점증관。분석인위，정격진동수착온도적승고이수지가극，기진동회복력회축점감소，사진동빈솔강저；원자상대운동회수온도적승고이가극，사득원자지간급정포지간적상호작용감약，치사성학모화광학모개출현홍이현상。수착온도적승고，봉관축점증관。저시유우수착온도적승고성자수축점증가，증가적성자진일보증가료산사개솔，종이강저료성자적평균수명，이성자적평균수명여봉관성반비，인차수착온도적승고봉관축점증관。성자모강도수온도승고정현불동규률，E2（LA），E2（TA），E1（TA）화A1（LA）성자모수착온도승고강도단조증가，이E2（TO），E1（TO）화A1（LO）성자모강도출현료선증후감적명현변화，재138 K강도출현겁대치。분석인위조성원인시유우당온도고우138 K시，고능량적성자분렬성다개구유경저능량적성자소치。
In the present paper ,Raman scattering techniques for N-type 4H-SiC single crystal material were performed at the temperatures ranging from 30 to 300 K .These measurements revealed that the Raman phonon modes have a redshift and the lin-ewidth gradually broadens with temperature increasing .Based on the experimental results ,the reason for the redshift and broad-ening is discussed .With the temperature increasing ,the lattice thermal vibration restoring force decreases with the lattice ther-mal vibration increasing ,and the interaction between the atom and unit cell is weakened ,resulting in the redshift of the acoustic phonon modes and optical phonon modes .The mean number of phonons increase with the temperature increasing ,which leads to an increase in scattering probability ,in result of decreasing the phonon lifetime .The linewidth and phonon lifetime is inversely proportional ,so the linewidth gradually broadens with temperature increasing .Phonon mode intensity with increasing tempera-ture showed different laws that the intensity of E2 (LA) ,E2 (TA) ,E1 (TA) and A1 (LA) phonon mode monotonously increases as the temperature increases ,while the intensity of E2 (TO) ,E1 (TO) and A1 (LO) phonon mode decreases after 138 K .The reason is that the high-energy phonons split into multiple lower energy phonons .