富Te条件下CdTe晶体中的点缺陷研究

Study on the Point Defects in Te-riched CdTe Crystals

基于缺陷化学理论,考虑到富Te的CdTe晶体中可能存在的点缺陷,建立了在Te气氛下退火时,热力学平衡态晶体中的点缺陷模型,其中包括Cd间隙(Cdi)、Cd空位(VCd)、Te间隙(Tei)和Te反位(TeCd)。利用质量作用定律和伪化学平衡方程计算了富Te情况下本征CdTe晶体中的点缺陷浓度和费米能级。计算结果系统的揭示了点缺陷浓度、费米能级、Te压以及退火温度之间的关系,发现只有TeCd浓度足够大时才能对费米能级产生钉扎作用。

In consideration of the possible point defects in Te-riched CdTe crystals,a thermodynamic equilibrium model for CdTe annealed under Te vapor was established based on the defect chemistry theory,native point defects,such as VCd,Cdi,Teiand TeCdwere included. Point defects concentration and Fermi level were both calculated using the mass action law and quasi-chemical equations. The results systematically reveal the relationship between the point defects concentration,Fermi level,Te vapor pressure and annealing temperature. The Fermi level was pinned only when TeCdconcentration was very large.