Coherent longitudinal optical phonon and plasmon coupling in the near-surface region of InN
Coherent longitudinal optical phonon and plasmon coupling in the near-surface region of InN
复制标题
InN 近表面区域的相干纵向光学声子和等离子体耦合
DOI：
--
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
W. Schaff
中科院分区：
文献类型：
--
作者：
Yu;C. Chuang;C. Chia;K. Tsen;Hai Lu;W. Schaff
利用时间分辨二次谐波产生技术，实现了高质量InN外延层的相干声子光谱。在光谱中只能分辨出447cm−1的相干纵向声子和等离子体耦合模式。在1.5×1019cm−3范围内，其频率与光注入载流子密度无关。这一现象是由于相干A1（LO）声子与聚集在InN近表面区域的本禀冷等离子体的杂化，等离子体密度可达1020cm−3量级，远高于霍尔效应测量所得的散体浓度1×1018cm−3。
Coherent phonon spectroscopy of a high-quality InN epitaxial layer is carried out using time-resolved second-harmonic generation. A coherent longitudinal optical phonon and plasmon coupling mode only at 447cm−1 can be resolved in the spectrum. Its frequency shows no dependence on the photoinjected carrier density up to 1.5×1019cm−3. This phenomenon is attributed to the hybridization of a coherent A1(LO) phonon with the intrinsic cold plasma accumulated in the near-surface region of InN, where the plasma density could reach on the order of 1020cm−3, much higher than the bulk carrier concentration 1×1018cm−3 determined by Hall effect measurement.