Cu2Se、In2Se3、Ga2Se3混合球磨过程中的Cu(In,Ga)Se_2形成机制研究

Reaction Mechanism of Cu(In, Ga)Se_2 Formation During Milling Process of Powder Mixture of Cu_2Se, In_2Se_3 and Ga_2Se_3

对球磨时间不同的Cu2Se、In2Se3和Ga2Se3混合粉末进行热压烧结制备CIGS靶材,发现在球磨时间较短时靶材出现分层,随着球磨时间延长分层缺陷消失。由此考察了粉末在球磨过程中发生的物理化学变化及其对分层的影响。结果表明:Cu2Se、In2Se3和Ga2Se3三种硒化物粉末在球磨过程中发生机械合金化反应形成黄铜矿相Cu(In,Ga)Se2(CIGS)。随着球磨时间的延长,黄铜矿相结构Cu In Se2(CIS)首先在Cu-Se二元化合物表面产生,并随着Ga原子的扩散逐步形成CIGS四元相。当球磨时间达到48 h时,粉末由黄铜矿相CIGS和少量Ga2Se3组成。由于Cu2-xSe与CIGS晶体结构相近,因此通过外延反应的方式有效促进了CIGS的合成。球磨过程中Cu-Se二元相的消失和CIGS相的形成有助于抑制烧结过程中分层缺陷的产生。

Sputtering targets of CIGS quaternary ceramic were fabricated by hot-press sintering the milled powder mixture of Cu2 Se, In2Se3 and Ga2Se3. When the milling time of the powders less than 4 h,the sintered targets delaminated, while the delamination disappeared with the prolonging milling time.Therefore the physico-chemical changes of the powder mixture during the milling process and their influence on the delamination of the targets were investigated. The results indicate that with the progress of the milling process, mechanical alloying（MA） occurred, and chalcopyrite Cu（In, Ga）Se2（CIGS） formed from Cu2 Se, In2Se3 and Ga2Se3; With the increasing milling time, Cu In Se2（CIS） formed on the surface of binary copper selenide firstly and CIGS was subsequently generated due to the inward diffusion of Ga;Thus the original blend powders became a mixture of CIGS and residual Ga2Se3 after milling for 48 h.Since CIGS and Cu2- xSe have a similar crystallographic structure, therefore this epitaxial relation may facilitate the formation of CIGS. The disappearance of Cu-Se binary compound and the formation of CIGS restrained the delamination of the CIGS targets in the sintering process.