氧硒化鋅與碲硒化鋅等電性半導體之變溫載子復合機制研究

Abstract

本研究利用光激螢光光譜及時間解析光譜探討氧硒化鋅與碲硒化鋅等電性半導體材料載子隨著溫度變化的情形。我們發現碲硒化鋅在很寬的溫度範圍所呈現複雜的衰減路徑與拉伸函數完美的吻合。由於氧原子和碲原子電負度及原子尺寸的差異造成摻入硒化鋅後會產生不同的物理特性。隨著溫度上升，氧硒化鋅的生命期的呈現下降的趨勢與碲硒化鋅的生命期在70K前會先隨著溫度上升，而在70K之後碲硒化鋅的生命期隨溫度的上升而下降有顯著的對比。載子的復合機制與S型和V型的氧硒化鋅與碲硒化鋅的光激螢光峰值相符合。氧硒化鋅與碲硒化鋅不同的載子復合機制可以歸因於摻雜氧或碲而產生不同的能帶模型及侷限深度所導致。

This study investigates carrier relaxation dynamics of isoelectronic ZnSe1-xOx and ZnSe1-yTey semiconductors as a function of temperature using photoluminescence (PL) and time-resolved PL spectroscopy. We find that the complex decay traces of ZnSe1-yTey correlate excellently with the stretched exponential law within a wide temperature range. As the temperature increases, the monotonically decreased PL lifetime for ZnSe0.947O0.053 is in remarkable contrast to ZnSe0.950Te0.050 whose PL lifetime initially increases up to 70 K and then declines. These findings are consistent with the S- and V-shaped PL peak shift for ZnSe0.947O0.053 and ZnSe0.950Te0.050, respectively. The dissimilar carrier dynamics can be attributed to their extremely distinct band models and trapping depths.