利用分子束磊晶法成長硒化鎵薄膜之物性研究

Growth and Physical properties of GaSe thin films by molecular beam epitaxy

蔡宗廷(Tsung-Ting Tsai)

指導教授 ： 楊祝壽

大同大學/電機資訊學院/光電工程研究所/碩士(2010年)

摘要

我們嘗試研究非線性的硒化鎵（GaSe）薄膜晶體的物理特性。我們先以分子束磊晶法（MBE）在砷化鎵基板上成長硒化鎵磊晶層，並藉由改變硒/鎵流量比和基板溫度去探討其光學特性。從拉曼光譜中可以看到當鎵的溫度超過790℃之後,其磊晶層會從閃鋅礦結構的三硒化二鎵轉變成六角結構的硒化鎵。再進一步，去做一系列藉由改變鎵的溫度從790℃到860℃，去找出最適合成長硒化鎵磊晶層的條件。然而為了改善其光學性質，還控制了基板成長溫度從400℃到600℃，並且可以由光激螢光譜看到其能隙藍移從1.79 eV到2.03 eV。最後，由奈米壓痕量測系統可以測量出其硒化鎵磊晶層的硬度大約是硒化鎵塊材的兩倍。然而當鎵的溫度超過860℃時，其樣品表面會形成霧面，且推測可能是過量的鎵所造成的表面堆積。並且由原子力顯微鏡發現在此溫度下，其平均粗糙度的確是相對大於其他樣品。

關鍵字

硒化鎵薄膜

並列摘要

The GaSe epilayers were grown on GaAs substrates by molecular beam epitaxy. The growth parameters of III (Ga)–VI (Se) flux ratio and substrate temperature are modulated to grow and to investigate its optical properties. In Raman scattering spectra, the crystal structure are varied from zinc-blend Ga2Se3 to hexagonal GaSe as Ga cell temperature more than 790℃. Further, to find series appropriately conditions of GaSe epilayers by varying Ga cell temperature from 790℃ to 860℃. In order to ameliorate the optical properties, the growth temperature was controlled from 400℃ to 600℃, The PL spectra reveals an energy, blue shift of the main peak from 1.79 eV to 1.98 eV. Finally, the mechanical properties were investigated by Nano-Indenter system. The hardness of GaSe thin film is about two times to the bulk sample. When the Ga cell temperature is more than 860℃, it can observed the mist on the surface of GaSe epilaye, it might the excess of Ga accumulate on the GaSe surface. In atomic force microscope, the root mean square is also larger than others when the sample of Ga cell temperature more than 860℃.

並列關鍵字

GaSe ； MBE

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