硒化鎘鋅/硒化鋅調變摻雜氯單一量子井之分子束磊晶與物理特性分析

Molecular beam epitaxy and physical properties of modulation doped Zn0.86Cd0.14Se/ZnSe:Cl single quantum well

黃鴻鈞(Hung-Chuan Huang)

指導教授 ： 王智祥 ； 周武清

中原大學/理學院/應用物理研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500302

摘要

以分子束磊晶儀在砷化鎵(100)基板上成長硒化鋅摻雜氯的磊晶層；利用反射光譜及光激螢光光譜測量材料的光學特性。由光激螢光譜得知硒化鋅磊晶層摻雜氯之後依然有著良好的光性。此外並以霍爾效應量測法求出室溫時硒化鋅摻雜氯的磊晶層樣品的電阻率、載子濃度和載子遷移率。另外對光激螢光譜隨溫度變化的近能隙位置由瓦希尼(Varshni)關係式作模擬。再由光激螢光譜強度積分對溫度的變化得到激子活化能；且在摻雜源溫度110℃~130℃時，其活化能數值接近似於硒化鋅的自由激子與氯束縛激子的能量差。
此外，也利用分子束磊晶法在(100)砷化鎵基板上成長硒化鎘鋅/硒化鋅單一量子井，並以吸收光譜及光激螢光光譜定義光譜訊號。再成長硒化鎘鋅/硒化鋅調變摻雜單一量子井並改變其井寬、間隔層厚度與摻雜濃度，以光激螢光光譜量測其光學特性。由此暸解井寬、間隔層厚度與摻雜濃度對硒化鎘鋅/硒化鋅調變摻雜氯單一量子井的光性變化。並由實驗得知，樣品的光激螢光光譜能量位置會隨間隔層厚度的減少而增高；且在增加摻雜載子濃度後，也發現光激螢光光譜譜峰增大的結果。此現象則可以能帶彎曲效應(band bending effect)做合理解釋。此外，再由光激螢光譜強度積分對溫度的變化關係，了解間隔層對激子活化能並無明顯改變。

關鍵字

量子井 ； 摻雜 ； 二六族化合物半導體

並列摘要

Cl-doped ZnSe epilayers were grown on (100) GaAs substrates by molecular beam epitaxy. Optical properties were studied by photoluminescence (PL) and reflectivity (R) spectra. The resistance, carrier concentration and carrier mobility of Cl-doped ZnSe epilayers were obtained by Hall measurement. Temperature dependence of energy gap measured by PL spectra was fitted by the Varshni’s model. The energy gap in 0 K ( Eg(0) ) was obtained from the Varshni’s fitting. The temperature dependence of integrated PL intensity for the Cl-doped ZnSe epilayers can be expressed as I0 ( T ) = I0 (0) / [1 + D exp (-Ea / kT )]. The activation energy (Ea) of Cl-doped ZnSe epilayer with the doping cell temperature of 110℃ to 130℃ is very close to the energy separation between the free exciton( 2.806 eV) of ZnSe and the energy position (2.798 eV) of theCl bound exciton emission emission(Cl/X).
In addition, modulation doped Zn0.86Cd0.14Se/ZnSe:Cl single quantum well (MD-SQW) samples were also grown on (100) GaAs substrates by molecular beam epitaxy. Optical properties were investigated by the transmission and photoluminescence spectra. The PL peak energy increased with the decreasing spacer thickness. Moreover, the PL peak energy also increased with the increasing carrier concentration. The band bending effect was employed to explain this phenomenon. Furthermore, the study of temperature dependent PL integrated intensity shows that the activation energy is insensitive to the change of spacer thickness.

並列關鍵字

doping ； II–VI compound semiconductors ； quantum well

參考文獻

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