氧硒化鋅等電性半導體之光激螢光時間解析研究

Abstract

在摻雜氧的硒化鋅中，氧會形成等電性中心並抓住載子，這將使載子的復合路徑變得複雜。在本研究中，我們使用光激螢光光譜與時間解析光譜來探討氧對載子復合機制的影響 (氧硒化鋅的氧含量最高為5.3莫耳百分比) 。我們發現氧除了會造成很大的能帶彎曲外，也會對氧硒化鋅的生命期造成很大的影響。這個複雜的生命期衰減曲線可用柯爾洛希 (Kohlrausch) 的延伸性指數定律來描述，並可用電子的跳躍遷移模型做很好的解釋。除此之外，我們還發現隨著溫度升高，延伸參數 (β) 會出現先下降後上升的情形。這個結果反應了載子會因溫度上升而改變載子復合的機制。

Oxygen in ZnSe1-xOx acts as an isoelectronic trap that captures excitons and complicates the carrier relaxation paths. This study explores the influence of O on the carrier dynamics in ZnSe1-xOx (O content up to 5.3 %) by using temperature-dependent photoluminescence (PL) and time-resolved PL spectroscopy. Incorporating oxygen not only causes large band-gap bowing but also strongly affects the emission lifetime of ZnSe1-xOx. Kohlrausch’s stretched exponential law and hopping-transport model correlate well with the complex decay traces. Moreover, as the temperature increases, the stretching exponent β initially decreases and then monotonically increases. The results reflect a thermally activated transfer mechanism of carrier recombination.