Variation of the Fermi level in n-type microcrystalline silicon by electron bombardment and successive annealing: ESR and conductivity studies

ESR and conductivity studies have been preformed on μc-Si:H exposed to 2 MeV electron bombardment and successive annealing in order to investigate the influence of the defect density on the electronic properties of n-type μc-Si:H. With this approach one can vary the defect density in one and the same sample and directly deduce its influence on the electronic properties. The defect density is varied by 2 orders of magnitude with strong influence on the dark conductivity and electron spin resonance (ESR) properties. The relationship of ESR and conductivity data obtained over the whole defect density range is in agreement with the data obtained on the sets of samples deposited with different doping level. The results indicate that the Fermi level position in μc-Si:H is defined by a balance of defect and donor states densities regardless of which of these quantities is varied. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)