Space charge limited current, variable range hopping and mobility gap in thermally evaporated amorphous InSe thin films

Abstract

We have analyzed the properties of as-deposited InSe thin films, deposited onto well cleaned glass substrates under a vacuum of 10−5 Torr, using X-ray diffraction, Rutherford back scattering, energy dispersive analysis of X-rays, optical transmittance and current–voltage (120–390 K) measurements. Allowed and indirect transition was identified and the mobility gap was determined as 1.44 eV. Under low field ( 2×105 V cm−1) and in the temperature range of 300–390 K, space charge limited conduction currents (SCLC) mechanism was observed and the related parameters, such as electron density (n0), trap density (nt), the ratio between free electron density to the total electron density (Θ), mobility (μ) and the effective mobility (μeff) of the InSe film of typical thickness 265 nm were calculated and the results are discussed.