分子束外延生长的n型Al掺杂ZnS1-xTex深中心研究

应用电容-电压、光致荧光和深能级瞬态谱技术研究了分子束外延生长的n型Al掺杂ZnS_1-xTe_x外延层深中心.Al掺杂ZnS_0.977Te_0.023的光致荧光强度明显低于不掺杂的ZnS_0.977Te_0.023，这表明一部分Al原子形成非辐射深中心.Al掺杂ZnS_1-xTe_x(x=0，0.017，0.04和0.046)的深能级瞬态傅里叶 关键词：

DEEP ELECTRON STATES IN n-TYPE Al-DOPED ZnS1-xTex GROWN BY MOLECULAR BEAM EPITAXY

Capacitance-voltage (C-V), photoluminescence (PL) and deep level transient spectroscopy (DLTS) techniques were used to investigate deep electron states in n-type Al-doped ZnS_1-xTe_x epilayers grown by molecular beam epitaxy (MBE). The integrated intensity of the PL spectra obtained from Al-doped ZnS_0.977Te_0.023 is lower than that of undoped ZnS_0.977Te_0.023，indicating that some of Al atoms form nonradiative deep traps. Deep level transient Fourier spectroscopy (DLTFS) spectra of the Al-doped ZnS_1-xTe_x(x=0，0.017,0.04 and 0.046,respectively) epilayers reveal that Al doping leads to the formation of two electron traps at 0.21 and 0.39eV below the conduction band. DLTFS results suggest that in addition to the roles of Te as a component of the alloy as well as isoelectronic centers, Te is also involved in the formation of an electron trap, whose energy level relative to the conduction band decreases as Te concentration increases. Our results show that only a small fraction of Al atoms form nonradiative deep defects, indicating clearly that Al is indeed a very good donor impurity for ZnS_1-xTe_xepilayers in the range of Te concentration studied in this work.