Stability and electronic properties of amorphous silicon p-i-n devices fabricated using ECR plasma enhanced chemical deposition

Abstract

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Properties of a-(Si,Ge) films and devices deposited at high growth rates

“…The plasma beam impinges on the sample and reacts with the silane and germane introduced near the substrate to cause growth of the film [27]. The plasma potential and plasma density reaching the substrate are known to be functions of pressure in the reactor and the power density of the incoming microwave beam, which excites the plasma [28].…”

“…Devices operating at reverse bias are less susceptible because the internal field is larger. The back diffusion is further enhanced by The ratio of the QE values under zero and forward bias (Figure 3.8) provides a diagnostic tool [28]. A high ratio at lower wavelengths indicates a problem with the player or p-i interface.…”

“…A high ratio at lower wavelengths indicates a problem with the player or p-i interface. When the bandgap of the buffer layer is too high, a notch develops [28,29] in the valence band between the buffer layer and the i-layer, leading to trapping of holes. This increases the QE ratio at short wavelengths.…”

“…collected. An external voltage helps to distinguish between the two types of holes, as shallow holes do not need significant field assist to be collected [28].…”

“…A schematic of the setup is shown in Appendix B.A linear plot of logcr vs T 1 could indicate either band-like conduction beyond a sharp mobility edge or phonon-assisted hopping between nearest-neighbour localized states. Alternatively, a concave upward logcr vs. T 1 plot could reflect either the absence of a sharp mobility edge or the predominance of variable range hopping conduction[28].…”