In view of using doped nanocrystalline Si (nc-Si) as the emitter layer in nc-Si/crystalline-Si heterojunction solar cells, a very thin (≤ 50 nm) emitter layer with high conductivity and superior crystallinity is optimum. In the present work, p-nc-Si:H thin film prepared in inductively coupled plasma chemical vapor deposition, without using additional H₂-dilution in [SiH₄ + B₂H₆ (1% in H₂)]-plasma, retains conductivity ~10⁻¹ S cm⁻¹ and crystallinity ~68% at a low thickness (t) ~50 nm. The charge carrier transport through the heavily doped nc-Si network demonstrates reverse Meyer–Neldel characteristics for t ≥ 50 nm. However, with reduction to t < 50 nm, the evolution of the ultra-nanocrystalline dominated amorphous network, accompanied by accumulation of Si–H–Si platelet-like components in the grain boundary, leads to a drastic reduction in conductivity to 10⁻⁴ S cm⁻¹. In this context, the post-deposition and short-time hydrogen plasma treatment (PSHPT) on the as-deposited ultra-thin (t ~30 nm) film becomes instrumental in substantially enhancing the crystallinity from 40% to 69% and increasing conductivity by two orders of magnitude to 10⁻² S cm⁻¹. The network modification by PSHPT proceeds via transformation of the surface and sub-surface weak bonds and is significant for the ultra-thin film compared to the thick film, due to retaining a superior surface-to-bulk ratio.

鉴于在nc-Si/晶体-Si异质结太阳能电池中使用掺杂纳米晶Si（nc-Si）作为发射极层，具有高导电性和优异结晶度的非常薄（≤50nm）的发射极层是最佳的。在目前的工作中，p -nc-Si:H 薄膜在电感耦合等离子体化学气相沉积中制备，无需在 [SiH ₄  + B ₂ H ₆ (H _{2 中}1% )]-等离子体中使用额外的 H _{2 -}稀释，保持电导率 ~10 ^-1  S cm ^-1在低厚度 (t) ~50 nm 下，结晶度 ~68%。通过重掺杂 nc-Si 网络的电荷载流子传输在 t ≥ 50 nm 时表现出反向 Meyer-Neldel 特性。然而，随着 t < 50 nm 的减少，超纳米晶主导的非晶网络的演变，伴随着晶界中 Si-H-Si 片状组分的积累，导致电导率急剧降低至 10 ^-4  S cm ^-1。在这种情况下，沉积后的超薄（t ~30 nm）薄膜上的沉积后和短时氢等离子体处理 (PSHPT) 有助于将结晶度从 40% 大幅提高到 69%，并将电导率提高两个数量级到 10 ^-2  S cm ^-1. PSHPT 的网络改性通过表面和亚表面弱键的转变进行，与厚膜相比，超薄膜具有重要意义，因为它保持了优异的表面与体积比。