成長於矽基板上的鍺基多重量子井之結構與光學特性分析

由於光學通訊相較於電子通訊有三大優點：(1)低耗損率：光通訊在光纖傳輸過程中耗損率相當低。(2)速度：光學通訊於真空中傳遞的速度遠勝於以銅線為載體的電子通訊。(3)頻寬：光通訊中，不同波長的光不會互相干擾，利用這點可以大大提升光學通訊的傳輸頻寬。綜合以上三點，發展光通訊元件將在未來的通訊領域中佔有重要地位。為了能製作可整合於現今積體電路之發光元件，本文探討成長於矽基板的鍺基多重量子井之結構與光學特性。本文使用拉曼光譜得知鍺/矽鍺多重量子井中鍺及矽鍺層的拉曼位移，接著使用經驗公式求出鍺層的拉伸應變為0.21%，而矽鍺層的鍺濃度為89%，拉伸應變為1.01%。藉由穿透式電子顯微鏡觀察鍺/矽鍺多重量子井各層的厚度，其中緩衝層的厚度只有120nm，未來製作波導型PIN發光元件將可因此減低光損失。接著使用光激螢光頻譜中得知螢光波長移至1540nm，此波長接近光通訊中能量損耗最低的波段。在發光效率方面，舊型量子井結構之能量因子為1.39，添加拉伸應變之量子井的能量因子為2.25，其發光效率勝於舊型量子井結構，發光行為由激子躍遷所主導，且激子主要由激發光源產生。鍺錫/鍺多重量子井方面，有兩片樣品，量子井結構為實驗組，另外成長同濃度的鍺錫薄膜為對照組，目的於探討量子井對於鍺錫材料之影響。本文於穿透式電子顯微鏡之影像中可觀察到缺陷都被緩衝層吸收。接著由二次離子質譜儀得知鍺錫/鍺多重量子井的二次離子質譜，結合二次離子質譜中不同材料的能量分佈及經驗公式求得鍺錫/鍺多重量子井中的錫濃度為2.27%。由光激螢光頻譜得知，鍺錫/鍺多重量子井的波峰為1725nm，鍺錫薄膜為1755nm，由於量子侷限效應使準費米能階向導電帶底部及價電帶頂部移動導致波峰往高能量移動30nm。鍺錫/鍺多重量子井的能量因子為2.57，鍺錫薄膜的能量因子為1.73，鍺錫/鍺多重量子井的發光效率勝於鍺錫薄膜，且發光行為主要由激發光源所產生的激子之躍遷主導。

關鍵字

能量因子；量子侷限效應；鍺/矽鍺多重量子井；拉伸應變；鍺錫/鍺多重量子井

並列摘要

Compared to electronic communications, optical communications has many advantages. So the development of optical communication components will play an important role in the field of communications at the future. In order to produce the light emitting element which can be integrated in today's integrated circuits. This paper discusses the structure and optical properties of Ge-based multiple-quantum-well on Si. We use Raman spectroscopy to know raman shift of Ge and SiGe layer in Ge / SiGe MQW. Then we determined the tensile strain of Ge layer is 0.21%, the tensile strain of SiGe layer is 1.01%, and the concentration of Ge is 89%by empirical formula. We discover the thickness of buffer layer in Ge / SiGe MQW by TEM is only 120nm. It will reduce the optical loss in produce waveguide type PIN-emitting element at Future By Photoluminescence, We observe that the wavelength of luminescence move to 1540nm which is the lowest energy loss in optical communication. In luminous efficiency, The power factor of old QW structure is 1.39. And MQW with tensile strain is 2.25. The luminous efficiency is better than the old one. And luminescence is dominated by excitonic transition which is produced primarily by the excitation light source. For the purpose to investigate the impact between GeSn/Ge MQW and Ge film. We have two samples, GeSn/Ge MQW as experimental group and GeSn film as the control group. We observed the defects were absorbed in the buffer layer by TEM. And we find out the concentration of Sn in GeSn/Ge MQW is 2.27% by SIMS. By Photoluminescence, we aware of the luminescence wavelength of GeSn/Ge MQW is 1725nm and Ge film is 1755nm.The reason is the quasi-fermi level will move to the bottom of the conductive band and the top of valence band by quantum confinement effect.The power factor of GeSn/Ge MQW is 2.57 and Ge film is 1.73. The luminous efficiency is better than Ge film. And luminescence is dominated by excitonic transition which is produced primarily by the excitation light source.

並列關鍵字

Power factor ； Quantum confinement effect ； Ge/SiGe Multiple quantum well ； Tensile strain ； GeSn/Ge Multiple quantum well

參考文獻

elch, “Single-chip 40-channel InP transmitter photonic integrated circuit capable of aggregate data rate of 1.6 Tbit/s, ” Electronics Letters. 42(13), 771-773 (2006).

[8]J. Liu, X. Sun, D. Pan, X. Wang, L. C. Kimerling, T. L. Koch, and J. Michel,“Te-nsile-strained, n-type Ge as a gain medium for monolithic laser integration on Si,”Optics Express. 15(18), 11272 (2007).

[9]M. V. Fischetti, and S. E. Laux,“Band structure, deformation potentials, and carrier mobility in strained Si, Ge, and SiGe alloys, ” Journal of Applied Physics 80(4), 2234-2252 (1996).

[11]Richard A. Soref, and Clive H. Perry. “Predicted band gap of the new semicoductor SiGeSn, ” Journal of Applied Physics. 69(1), 539-541 (1991).

[14]J. Weber, and M. I. Alonso,“Near-band-gap photoluminescence of Si-Ge alloys

國際替代計量

成長於矽基板上的鍺基多重量子井之結構與光學特性分析

未授權

主題瀏覽