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本文报道了通过电导和光电导的测量,了解用硅烷辉光放电工艺制备非晶态硅薄膜(简称GD-aSiHx)的基本特性。试验结果指出,我们制备的GD-aSiHx本征薄膜具有显著的光电导效应,光照下可使其电导率增加两个数量级。从吸收系数和光谱灵敏度曲线得到GD-aSiHx的迁移率隙Eg为1.65eV。在Eg1.65eV处有强光响应,而在定域态1.65—0.75eV之间有弱光响应,低于0.75eV无光响应,足见我们制备的GD-aSiHx为弱n型半导体。发现光生载流子移向Ec时,双分子复合作用占主导地位。所进行的低温和高温电导和光电导测试结果表明,GD-aSiHx的低温电导随温度下降而降低,并与温度倒数1/T呈函数关系。电导由激活过程逐渐变为非激活过程,激活能为0.66—0.73eV。高温电导曲线表明电导随温度升高而增大,但电导与温度呈非线性关系,说明GD-aSiHx的电子传导是通过跃迁输运的。对低温下光电导用R_D/R_L表示时(R_D是暗阻,R_L是光阻),当T=293-193K,(R_D/R_L)低温:(R_D/R_L)室温≈10;T<193K,R_D≈R_L;高温下光电导R_D/R_L随温度升高而降低;当T>373K时,R_D≈R_L。
In this paper, the basic characteristics of amorphous silicon films (referred to as GD-aSiHx) prepared by silane glow discharge process are reported through the measurement of conductance and photoconductivity. The experimental results show that GD-aSiHx intrinsic film prepared by our method has significant photoconductivity, which can increase its conductivity by two orders of magnitude under light irradiation. From the absorption coefficient and spectral sensitivity curve GD-aSiHx mobility gap Eg was 1.65eV. There is a strong light response at Eg1.65eV and a weak light response between 1.65-0.75eV at localized and less than 0.75eV no dull response, which indicates that GD-aSiHx is a weak n-type semiconductor. When the photo-generated carriers move to Ec, bimolecular recombination plays a dominant role. The results of low temperature and high temperature conductivity and photoconductivity tests show that the low temperature conductance of GD-aSiHx decreases as the temperature decreases, and it is a function of the reciprocal temperature 1 / T. Conductance gradually changes from an activation process to an inactive process, with an activation energy of 0.66-0.73 eV. The high temperature conductance curve shows that the conductance increases with increasing temperature, but the conductance is non-linear with the temperature, indicating that the electron conduction of GD-aSiHx is transported by the transition. (R_D / R_L) low temperature: (R_D / R_L) room temperature ≈10; T <193K, when R = R_D ≈ R_L; photoconductive R_D / R_L at high temperature decreases with increasing temperature; when T> 373K, R_D ≈ R_L.