分子束磊晶成長之硒化鎘鋅磊晶層和硒化鋅/硒化鎘鋅多重量子井的光學特性量測

Optical Properties of Zn1-xCdxSe Epilayers and ZnSe/ Zn1-xCdxSe Multiple Quantum Well Grown by Molecular Beam Epitaxy

施采萱(Tsai-Hsuen Shih)

指導教授 ： 周武清

中原大學/理學院/應用物理研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200097

摘要

利用分子束磊晶法在(100)砷化鎵基板上成長硒化鎘鋅磊晶層。使用(004)雙晶繞射儀量測硒化鎘鋅磊晶層之晶格常數，半高寬值的範圍為475 秒 到2100 秒。使用光激螢光譜量測隨溫度變化的能隙。利用瓦希尼(Varshni)與歐德尼爾(O’Donnell)關係式去作模擬。瓦希尼(Varshni)與歐德尼爾(O’Donnell)公式模擬得到與聲子能量有關的參數β值為161K到368K，聲子平均能量()值為13 毫電子伏特到24毫電子伏特。由光激螢光譜積分的亞倫尼斯(Arrhenius)圖法得到激子活化能之值隨著鎘濃度增加而減少。利用縱向光學聲子、雜質及聲學聲子等互動參數作為隨著溫度改變之光激螢光譜線寬之理論模擬分析。取得雜質束縛能量隨著鎘濃度增加而減少。
利用分子束磊晶法在(100)砷化鎵基板上成長硒化鋅/硒化鎘鋅多重量子井。使用反射與光激螢光譜量測材料的光學特性。運用光激螢光譜積分的亞倫尼斯(Arrhenius)圖法得到激子活化能之值隨著硒化鎘鋅位能井寬度增加而減少。利用縱向光學聲子、雜質及聲學聲子等互動參數作為隨著溫度改變之光激螢光譜線寬之理論模擬分析。縱向光學聲子偶合參數隨著硒化鎘鋅位能井寬度變寬而增加。雜質束縛能量隨著硒化鎘鋅位能井寬度增加而減少。

關鍵字

分子束磊晶

並列摘要

Zn1-xCdxSe epilayers were grown on (100) GaAs substrates by molecular beam epitaxy. Lattice constants of the epilayers were measured by the (004) rocking curve X-ray diffraction. Full width at half maximum (FWHM) of 475 to 2100 arcsec was obtained. Temperature dependence of energy gap, measured by the photoluminescence (PL) spectra, was fitted by the Varshni’s and O’Donnell’s models. Phonon energy related fitting parameters β (161K to 368K) and (13 meV to 24 meV) were obtained from the Varshni’s and O’Donnell’s fits, respectively. Activation energies calculated from the Arrhenius plot of the integrated PL show a decrease with the Cd composition. PL line-width broadening with temperature was fitted byΓ( T )=Γ0+ΓaT +ΓLO1/[exp( ħωLO1 / kT )-1] + ΓLO2/[exp( ħωLO2 / kT )-1] + Γi exp(-/ kT ). The impurity binding energy, , was found to decrease with increasing Cd composition.
ZnSe/Zn1-xCdxSe multiple quantum wells ( MQWs ) were also grown on (100) GaAs substrate by molecular beam epitaxy. Optical properties were measured by reflectivity and photoluminescence spectra. The exciton activation energy obtained from the Arrhenius plot of the integrated PL was found to decrease with ZnCdSe layer thickness. The fitting of PL line-width broadening with temperature shows a decrease in the exciton-longitudinal optical (LO) phonon coupling as the ZnCdSe well width is reduced. The impurity binding energy, , was also found to decrease with ZnCdSe thickness.

並列關鍵字

MBE

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