电沉积工艺对p-CuSCN薄膜结构及半导体性质的影响

以乙二胺四乙酸二钠(ethylenediamjn tetraacetic acid disodium,EDTA)为鳌合剂,在水溶液络合体系中采用电沉积法制备了CuSCN半导体薄膜,应用电子隧穿成核和表面态热激发机理以及Mott-Schottky曲线分析了沉积电位和温度对薄膜结构和半导体性质的影响.结果表明:室温下,价带电子隧穿产生的电流与表面态空穴热激发电流在同一数量级,表面态空穴热激发电流不随电位改变,价带电子隧穿电流的变化趋势反映了整体电流的变化.随着阴极电位的升高,由于价带电子的隧穿几率变化,晶粒尺寸先减小后增大;半导体空穴浓度减小,p型性质减弱.由于沉积反应受活化能控制,在高温条件下主要表现为晶粒生长,导致晶粒尺寸增大,薄膜致密度降低;同时也使半导体空穴浓度减小,p型性质减弱.

INFLUENCE OF ELECTRODEPOSITION PROCESSING ON MICROSTRUCTURE AND SEMICONDUCTING CHARACTERISTICS OF p-CuSCN THIN FILM

CuSCN semiconducting thin films were prepared by electro-deposition with aqueous solution using ethylenediamine tetra- acetic acid disodium (EDTA) as chelating agent. Based on the mechanisms of electron tunneling nucleation and thermal activation of surface states as well as the Mott-Schottky curve, the influence of deposition potential and temperature on microstructure and semi- conducting characteristics of CuSCN thin films is discussed. Result shows that the current caused by thermal activation of the surface state hole has the same order of magnitude with electron tunneling current,and the thermal activation current of by surface state hole no change with the increasing of deposition potential, and electron tunneling current through valence band determines change of the whole current at room temperature. With cathode potential hoisting, due to the change of nucleation probability for the electron tun- neling through valence band, the CuSCN crystal size first decreases and then rises,and the hole concentration reduces in the CuSCN crystal,and the p-type characteristics of the thin films weaken. Meanwhile, owing to depositing reaction was controlled by activation energy, with temperature rising, the growth of crystal grain is predominant, leading to bigger grain size, higher porosity and weaker p-type characteristics of thin films.