矽摻雜氮化鎵薄膜之特性研究

Abstract

我們的實驗以低壓有機金屬氣相磊晶法成長矽摻雜氮化鎵，在改變不同四氫化矽流量以得到不同矽摻雜濃度的試片，藉以了解 N 型氮化鎵薄膜在摻雜矽後之光電行為變化。 PL 的量測結果顯示，矽的摻雜造成能階的位移和譜線變寬的行為，同時黃光的躍遷強度亦會隨摻雜量的增加而減小。這可能是因為矽的加入取代了氮化鎵薄膜中之鎵，改變了因為鎵空缺造成之深層受子對電子的影響。由變溫霍爾量測得知，矽摻雜氮化鎵之施子能階約在 26.5 meV ，與室溫之熱能相當，在室溫下施子雜質之電子可以大比例的躍遷至導電帶，這說明了矽的確是適當的 N 型氮化鎵摻雜源。

The Si-doped GaN films grown by metalorganic chemical vapor deposition have been thoroughly studied by using X-ray 、Raman spectra and PL as well as variable temperature Hall measurement. PL spectra indicate that the near-band edge transition is blue shift and the linewidth is increased as the doping concentration is increased. Moreover, it is also found that the intensity of near-band edge transition becomes stronger, and the intensity ratio of yellow emission to near-band transition drops significantly with Si doping concentration. This could attribute to the substitution of Si atoms on Ga sites, that reduce defects of Ga vacancy, and hence the corresponding yellow emission. Finally, a variable-temperature Hall measurement was also used to characterize the Si doped GaN samples. The measured activation energy is 26.5 meV below conduction band, comparable to thermal energy at 300K, which suggests the Si is an appropriate N-type doping impurity for GaN.