Effect of changing Gallium arsenide content on Gallium arsenide–polymer composite varistors

• Novel semiconductor–polymer composite varistors are introduced.
• Lower breakdown voltages can be reached due to increasing GaAs content.
• Nonlinearity of varistors and their band gaps increase by increasing GaAs content.
• Lifetime of varistors increases through increasing polymer content.
• The varistors could be used many times with low degradation.

GaAs–polymer composites have been prepared using the hot pressing method and their current–voltage characteristics have been studied. The results show that samples with GaAs content exceeding 50% of the whole composition have varistor behavior. They can be used to protect circuits from 60 V up to over 90 V voltages. In addition, it is found that the higher the content of GaAs in the varistor, the lower the breakdown voltage. Samples with higher polymer content have less nonlinearity. Each composite varistor has hysteresis which increases through increasing GaAs content. Main results have been analyzed with respect to SEM micrographs of the samples and compared with reported results for ZnO–polymer composite varistors. Energy gaps of varistors are evaluated using both (ln(σ)–1/T) diagram and their UV spectra analysis regarding Tauc relation. UV spectra show that reducing the GaAs content in the varistors causes their absorptions and corresponding impurity band gap to decrease.