摘要
研究了 Zn S1 - x Tex(0 .0 2≤ x≤ 0 .3)混晶的静压光致发光谱 .每块样品都观察到一个峰值比相应混晶带隙低很多的发光峰 ,来源于束缚在 Ten(n≥ 2 )等电子陷阱上的激子复合发光 ,且随压力 (0～ 7.0 GPa)而蓝移 .发光峰的压力系数比相应混晶带边的都要小 ,随着 Te组分的增加而减小 ,与混晶带隙压力系数的差别也越来越大 .由于压力下与发光峰对应的吸收能量逐渐接近并超过激发光的能量 ,与发光峰有关的吸收效率降低 ,发光峰积分强度随着压力增加而减小 .据此估算了 Ten 等电子中心的 Stokes位移 .发现 Stokes位移随着
The pressure behaviors of photoluminescence emissions of ZnS 1-x Te x (0 02≤ x ≤0 3) mixed crystals are studied at room temperature.One wide emission band with peak energy much lower than corresponding band gap of the mixed crystal is observed for each sample,which are ascribed to the radiative annihilations of excitons bound at Te n (n ≥2) isoelectronic centers.The pressure coefficients of the emission bands are all smaller than those of the mixed crystals band gap and decrease with the Te composition,but the discrepancy of pressure coefficient between the emission band and corresponding alloys band gap increases.The absorption efficiency related to the emission band decreases due to the absorption energy approaches and exceeds the laser energy with pressure,that leads to the decrease of the integrated intensity of the emission bands.According to this model the Stokes shifts of Te n centers are calculated,which decreases with Te composition.
基金
国家自然科学基金资助项目 (批准号 :60 1760 0 8)~~
