半導體異質結構之光學研究

Optical studies of semiconductor heterostructures

陳自平(Tzu-Ping Chen)

指導教授 ： 沈志霖

中原大學/理學院/應用物理研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200210

摘要

摘要
本論文利用無接點式電場調制反射光譜（contactless electroreflectance-CER）及光激螢光(Photoluminescence-PL)量測技術，研究摻雜不同濃度鈥（Ho）之磷砷化銦鎵（InGaAsP）磊晶層，及不同濃度銦的氮化銦鎵/氮化鎵（InGaN/GaN）多層量子井(MQWs)發光二極體（LEDs）結構。
量測溫度為14 K時，發現摻雜鈥樣品的調制反射光譜，隨摻雜鈥濃度由0～0.110 wt％變化，其展寬變小，因此於磷砷化銦鎵磊晶層中摻雜適量的鈥會使此材料發光特性變好。量測溫度為110 K時，討論摻雜鈥使樣品產生應變之大小。此外改變溫度由14～300 K，其能隙位置有紅位移現象符合Varshni及O’Donnell理論模型。
研究量子井中銦濃度為18～20 wt％之氮化銦鎵/氮化鎵樣品，在改變溫度的電場調制反射光譜，發現其能隙有二個區段不同之變化。以時間鑑別光激螢光量測系統（time-resolved photoluminescence-TRPL）量測此樣品，發現躍遷能量強度隨時間的衰變在低能量部分比高能量部分慢，隨銦濃度增加螢光衰減時間加長。在不同濃度銦光激螢光光譜中，發現隨濃度增加其半高寬變寬，這些現象皆可由不均勻的銦產生的侷限效應加以解釋。

關鍵字

無接點電場調制反射光譜 ； 時間鑑別光激螢光光譜 ； 磷砷化銦鎵 ； 氮化銦鎵

並列摘要

ABSTRACT
Contactless electroreflectance(CER) and photoluminescence(PL) measurements were used to study the structural properties of Ho-doped InGaAsP epilayers and InGaN/GaN multiple quantum wells(MQWs) light emitting devices(LEDs).
The broadening parameter of the InGaAsP band-to-band transition at 14 K was found to decrease from 0~0.110 wt%. A strain-induced splitting of the valence band in Ho-doped InGaAsP layers has been found in CER spectra at 110 K. The red-shift of transition energy in the temperature range 14~300 K was fitted by Varshni relation and O’Donnell formula.
The InGaN/GaN MQWs LEDs with In content about 18~20 wt% was analyzed with temperature dependent CER. Two regions of transition energy were found in different temperature ranges. This sample was also measured by time-resolved photoluminescence(TRPL). The time decay of transition intensity at lower energy is slower than that at higher energy. The decay time of PL increases with In concentration. The FWHM of PL spectra increases with In concentration. These results were interpreted in terms of localization induced by inhomogeneous In concentration.

並列關鍵字

InGaN/GaN ； InGaAsP ； contactless electroreflectance ； time-resolved photoluminescence

參考文獻

[5] R. Saito, and T. Kimura, Phys. Rev. B 46, 1423 (1992).

[9] D. E. Asepns, “Modulation Spectroscopy/Electric Field Effects on the Dielectric Function of Semiconductors”Bell Laboratories. (1980).

[10] R. K. Ahrenkiel, “Measurement of Minority-Carrier Lifetime by Time-Resolved Photoluminescence,” Solid State Electron. 35, 239 (1992).

[11] M. Smith, G. D. Chen, J. Y. Lin, H. X. Jiang, and M. A. Khan, Q. Chen, “Time-Resolved Photoluminescence Studies of InGaN Epilayers,” Appl. Phys. Lett. 69, 2837 (1996).

[13] Dunbar, U. Bangert, P. Dawson, M. Halsall, Y. Shiraki, M. Miura, I. Berbezier, B. A. Joyce, and J. Zhang, “Structural, Composition and Optical Properties of Self-Organised Ge Quantum Dots,” Phys. Stat. Sol. (b) 224, 265 (2001).