ABSTRACTDeposition of n and p-type amorphous (a-Si:H) and microcrystalline (µc-Si:H) silicon thin films on polyethylene terephthalate (PET) at substrate temperatures (T_sub) of 100°C and 25°C (RT) prepared by hot-wire (HW) chemical vapor deposition and radio-frequency (RF) plasma-enhanced chemical vapor deposition is studied as a function of hydrogen dilution. Doping is achieved by addition of phosphine (ntype) and diborane (p-type) to the gas phase reactive mixture. At Tsub=100°C, n-type a-Si:H is obtained by HW with dark conductivity σ_d10⁻⁴ ω⁻¹cm⁻¹ and by RF with σ_d~10⁻³ ω⁻¹cm⁻¹. P-type a-Si:H is obtained by HW with σ^d=8×10⁻⁷ ω⁻¹cm⁻¹ and by RF with σ_d=6×10⁻⁷ ω−₁cm⁻¹. Decreasing the temperature of deposition to 25°C decreases the sd of RF n-type amorphous samples to 5×10⁻⁵ ω⁻¹cm⁻¹ but the σ_d of p-type samples remains unchanged. RT HW a-Si:H films show a decrease of sd both for ntype film (σ_d=4×10⁻⁶ ω⁻¹cm⁻¹) and p-type film (σ_d=1.2×10⁻⁷ ω⁻¹cm⁻¹). N-type µc-Si:H was obtained by HW with σ_d=7×10⁻² ω⁻¹cm⁻¹ and by RF with σ_d>10⁻² ω⁻¹cm⁻¹ at 100°C. Using the same T_sub, p-type µc-Si:H was deposited by HW and by RF with σ_d~0.5 ω⁻¹cm⁻¹. At RT, only p-type µc-Si:H films could be prepared using HW (σ^d~1 ω⁻¹cm⁻¹) and RF (σ^d=4×10⁻³ ω⁻¹cm⁻¹). The structural properties of the films were studied using Raman spectroscopy. The structural and transport properties were correlated.