In muc-Si:H layers deposited on substrates at various temperatures, the relaxation of the mobility, density of the equilibrium, photogenerated and injected charge carriers using extraction by linearly increasing voltage method has been investigated. We found that in muc-Si:H layers, especially those deposited at low temperature, charge carrier mobility decreases with time, the charge carrier density relaxation is much slower, and the charge carrier dispersion is higher than in a-Si:H. (C) 2003 Elsevier B.V. All rights reserved.