H layers

Next, observe that the x-directiqn displacements of e h layer are... 

The general form that is used in EMTs to describe the dielectric function e of an fl-Si H layer with a certain fraction of voids is given by [345]... 

In a real-time spectroellipsometric measurement in which the kinetics of a-Si H deposition is studied, trajectories are recorded in the A-4 plane at various photon energies between 2 and 4 eV. These trajectories can be simulated and fitted to models that represent the growing a-Si H layer. Canillas et al. [347] have made a detailed study of the deposition of the first few layers of a-Si H on a NiCr/glass substrate. Similar results are obtained for a c-Si substrate. They have proposed several models to explain the data. One possible model is the hemispherical nu-cleation model, which describes a hexagonal network of spherical a-Si H nuclei located at an average distance d between them. The growth is represented by an... 

The purpose of the n-type doped a-Si H layer is to prevent injection of charge from the substrate into the photoconductor. Thus it serves as a blocking layer. Injection of surface charge into the photoconductor is prevented by the surface... 

The corona discharges produces oxygen ions and ozone, which may react with the photoconductor [634], As a means to circumvent possible degradation of the surface layer, an extra, protective thin layer was proposed, with high carbon content [101, 635, 636]. This would reduce silicon-oxygen reactions at the surface. Excellent electrophotographic characteristics have been obtained with a thin device comprising a 0.1-/rm-thick n-type a-Si H layer, a 1.0-/rm intrinsic a-Si H layer, a 0.1-/irm undoped a-SiCo i H layer, and a 0.014-/xm undoped a-SiCoj H layer [101]. 

Prototype electrostatic loudspeakers where the graphite is replaced by a-Si H have been made, where a Mylar foil (area 10 x 10 cm-, thickness 6 /im) is used [657]. Deposition of the a-Si H layer was carried out in the ASTER deposition system. Uniform deposition (standard deviation of thickness, 1.5%) was achieved by diluting the SiHa with Ht with SiHa Hi = 1 2 [370]. The deposition was at room temperature. The hydrogen content amounted to 18 at.%, and the bandgap was 1.81 eV. The dark conductivity and AM 1.5 photoconductivity were 7.5 X 10 and 1.8 x 10 cm" , respectively. In practice the film would not... 

Incorporated in a device, the LPCVD -Si H material shows electroluminescence only in reverse bias [673]. The mechanism is similar to the one described for c-Si. The PECVD a-Si H material was incorporated in a p-i-n solar cell structure, with a thickness of the intrinsic layer of 500 nm (see Section 1.11.1). Oxygen was coimplanted at 80 keV (3.2 x 10 O/em-) and at 120 keV (5.5 x lO 0/cm ), which resulted in a roughly constant oxygen concentration of 1.0% in the Er projected range in the middle of the intrinsic a-Si H layer. Electroluminescence is observed under forward bias [674]. 

H layer 4 G 21, parallel incised lines inside bottom... 

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