探討鈉摻雜對脈衝雷射沉積銅銦鎵硒薄膜 的物理特性影響之研究

Abstract

在本研究中，我們主要探討鈉摻雜對銅銦鎵硒薄膜特性之影響。我們先利用脈衝雷射沉積銅銦鎵硒薄膜(CIGS)、再透過電子束蒸鍍氟化鈉(NaF)和經由不同溫度(100℃與200℃)快速熱退火技術製作而成鈉摻雜的銅銦鎵硒薄膜(NaA100和NaA200)。並經由XRD、Raman、FTIR及Hall觀測樣品的物理特性。 透過XRD量測我們製備的CIGS薄膜(CIGS, NaA100, NaA200)為黃銅礦結構，且NaA100於(112)軸向有最小的半高寬。其結果顯示NaA100其鈉含量為1 wt%有最好的黃銅礦結構及結晶度。由Hall電性量測得知NaA100有最好的電性表現(電阻率為0.95 Ω∙cm、載子濃度為5.32×〖10〗^18 cm^(-3)，以及其遷移率為1.24 cm2V-1s-1)。再由變溫的電阻量測分析出NaA100的原子其有著最大的躍遷機率至正確的位置上，因此為最少空缺的薄膜。 由飛秒激發-探測光譜研究CIGS、NaA100和NaA200薄膜的超快載子動力學。我們觀測到經由能帶填充效應及熱聲子弛緩，使能隙發生重整於光激發位於價帶載子躍遷到導帶。由載子從導帶回到價帶的載子延遲過程，觀測到在薄膜中電子-聲子散射及與缺陷相關的非輻射複合。我們也觀測到NaA100有最長的與缺陷相關的非輻射復合時間，也進一步證實該薄膜的缺陷為最少。

In this work, we focused on the effects of sodium incorporation on CuIn1-xGaxSe2 thin films. We prepared the CIGS thin films by using pulsed laser deposition, and then evaporated the NaF via e-gun evaporation. Finally, the different Na-doping CIGS thin films (NaA100 and NaA200) were made with the various annealing temperature (100℃ and 200℃). These thin films were characterized utilizing the measurements of XRD, Raman, FTIR, and Hall. The polycrystalline feature with the chalcopyrite structure in these CIGS thin films (CIGS, NaA100, NaA200) examined in XRD patterns. The smallest FWHM of (112) orientation was observed in the NaA100 sample that indicated the best crystallinity under the Na-doping of 1wt%. The best electric properties also have been obtained after the annealing temperature of 100℃ (the resistivity of 0.95 Ω cm, the carrier concentration of 5.32×〖10〗^18 cm^(-3), the mobility of 1.24 cm2V-1s-1). By the result of temperature-dependent resistivity measurements, we analyzed the highest hopping probability of atoms which occurred in the sample of NaA100. The ultrafast carrier dynamics of these thin films were studied by the femtosecond pump-probe spectroscopy. The band filling and hot phonon relaxation both occurred while the process of carrier cooling. The longest defect-related non-radiative recombination lifetime was found in the sample of NaA100, which verified the much less defects in the films.