利用KrF脈衝雷射濺鍍成長硒化鎵薄膜及其光學特性研究

Abstract

我們以硒化鎵晶體當靶材並，用KrF脈衝雷射濺鍍法，成長硒化鎵薄膜在康寧玻璃上。當基板溫度450℃，脈衝重複頻率為20Hz，得到高指向性( 004 )的硒化鎵薄膜。在基板溫度400℃，變動雷射脈衝重複頻率，發現30Hz成長之樣品品質較佳，由半高寬估算粒子大小約為193 。室溫PL顯示約在2.13eV有一主要發光峰，與室溫硒化鎵( GaSe )晶體能隙2.05eV，比較稍微藍位移。假設量子強侷限效應( quantum size effect )造成之影響，估計粒子大小約為93 ，因此部分藍位移可能來自應力影響。550℃退火後樣品，從X-ray繞射圖也發現結晶性有改善。

We have used pulsed laser deposition to grow GaSe thin films on the corning glass from GaSe crystal target. under the substrate temperature 450℃ and the pulsed repetation rate 20 Hz , we obtained highly oriented GaSe thin film in the (004) direction . Varying the pulse repetation rate at the substrate temperature 400℃ , we found 30 Hz is the optimal pulse repetation rate from growing the thin film. From the FWHM of the X-ray data, the crystallite domain is 193 , from room temperature PL the edge emission at 2.13eV is slightly blue shift as compared of bandgap of 2.05eV of GaSecrystal at room temparature. We calculate the crystallite domain is 93 , according to the strong confinement quantum size effect. The over estimated result , indicates that the strain induced blue shift may not be negligible. The sample after annealing at 550℃ , is found the structure improving via X-ray diffraction.