在不同長晶條件下以垂直布氏長晶法生長之 AgGas2 單晶的材料結構與電性研究

Abstract

本研究主要在以垂直布氏長晶法生長 AgGaS2 單晶. 利用X光繞射法 以及穿透式電子顯微鏡來確認所長成之晶體在成份及結構上確為 AgGaS2 單晶的形態. 將我們所長出的晶體做塊材 X-Ray 的分析並與標準的 JCPDS 比對結果發現除了 AgGaS2 的繞射峰外尚有兩個可能為 Ga2S3 的 繞射峰存在. 若將試片與試片重量 0.05 % 的 Ag2S 一起封入石英管中進 行高溫熱處理後 Ga2S3 繞射峰己不存在. 在確定所長的單晶品質後, 我們嘗試加快(60mm/day)及減慢(15mm/day)長晶的速率, 以及拉高長晶時 的固/液相接面溫度梯度(44C/cm). 在塊材 X-Ray 的量測中可以看出愈慢 的長晶速度以及愈高的固/液相界面溫度梯度可以長出品質較好的單晶且 內部的析出物亦明顯的較少. In this study , we are interested in growing AgGaS2 single crystal by vertical Bridgman method . X-Ray diffraction and TEM are used to observe the constitution and structure of as-grown AgGaS2 crystal . By comparing the resultof bulk X-Ray with the JCPDS data three diffraction peaks , one from AgGaS2 andtwo from Ga2S3 , are found . The diffraction peaks of Ga2S3 are disappeared when heat treatment on AgGaS2 with 0.05wt.% Ag2S in sealed quartz tube is done. The growth conditions , including growth rate and temperature gradient , are tried to change and find out the best conditions to grow the crystal . Fromthe analysis of bulk X-Ray it indicates higher quality of crystal can be obtained under cinditions of slower growth rate and higher temperature gradient.And thus the density of precipitates decrease appraently .