Partial Carbonization of Aromatic Polyimide Films

Abstract

Aromatic polyimide films are partially carbonized between 700°C and 1000°C. Electrical conductivity and Hall coeficient have been measured. Electrical conductivity is higher at higher measuring temperatures. The electrical conductivity σ can be expressed as σ= σ₀exp (-E /kT), where k is the Boltzman constant. T is the absolute temperature. E depends upon the carborized temperature. The experimental data show the Hall coefficient R_H is negative, and this implies the carriers are negatively charged, i.e. electrons. The specimens are n-type semiconductors. The carrier density η can be expressed by η= A₁ exp (-E₁/κT) and carrier mobility μ can be expressed by μ = A₁exp (E₂/κT). E, E₁andE₂ depend upon the carbonized temperature