The Investigation of Quantum Effects of Band-Edge Modulated Nano-Structure Noncrystalline

带边调制的a-Si，N：H薄膜被用作带边调制的纳米结构非晶半导体，它是通过沿垂直于沉积薄膜的方向空间调制氮含量来制备的。在该薄膜中，导带的底部和价带的顶部沿该方向被空间调制，因为带隙随氮含量的变化而变化。证实了光学带隙能随薄膜的调制周期而变化。这可以用一维谐振子势模型来解释，该模型给出了作为调制周期的函数的两个带的最低量子化能级的分离。在这项研究中，我们尝试使用光吸收和光导技术来观察量子化能级之间的光学跃迁。我们已经开发了光学系统，使之能够观察这些跃迁。实验将一直进行到11K fo…用电子自旋共振(ESR)技术研究了带边调制a-Si，N：H薄膜的缺陷态及其量子效应。在调制周期为21-100Å的薄膜中，硅悬挂键的g值在2.0031-2.0039之间。没有观察到g值与调制周期的依赖关系。从g值可以看出，引起ESR的磁中心是由硅悬挂键识别的，硅悬挂键与氮有三个背键，与氮有两个背键，与硅有一个背键。这些悬垂的键存在于富氮区域。它们是深中心，因此g值不受量子效应的影响。自旋密度随调制周期的减小而增加，因为富氮区变得更加无序。带边调制薄膜的发光是由单态激子、三态激子和电子-空穴对的辐射复合引起的。研究发现，调制势的限制效应使激子更加稳定。较少

The band-edge modulated a-Si, N : H films are used in this study as band-edge modulated nano--structure-noncrystalline semiconductors, which are fabricated by spatially modulating nitrogen content along a direction perpendicular to the deposited film. In this film, the bottom of conduction band and the top of valence band are spatially modulated along this direction, because the band gap is varied by nitrogen content. The optical gap energy has been confirmed to be varied by the modulation period of the film. This can be accounted for in terms of one-dimensional harmonic oscillator potential model giving the separation of the lowest quantized levels of both bands as a function of the modulation period.In this study, we have attempted observations of optical transitions between the quantized levels, using the techniques of optical absorption and photoconductivity. We have developed the optical system making enable to observe these transitions. The experiments are going on down to 11K fo … More r this purpose.The defects states and their quantum effects of the band-edge modulated a-Si, N : H films have been investigated using the electron spin resonance (ESR) technique. The observed g-values of silicon dangling bonds range between 2.0031-2.0039 in the films of modulation periods of 21-100Å. No dependence of the g-value on the modulation period has been observed. From the g-values, the magnetic centres responsible for ESR are identified by silicon dangling bonds having three back-bonds with nitrogen and having two back-bonds with nitrogen and one back-bond with silicon. These dangling bonds exist in the nitrogen-rich region. They are deep centres so that the g-value is not affected by quantum effect. The spin density is increased with decreasing the modulation period because the nitrogen-rich region becomes more disordered.The luminescence of the band-edge modulated films arises from radiative recombination of singlet excitons, triplet excitons and electron-hole pairs. The excitons are found to be more stabilized by the confinement effect of modulated potentials. Less