Change of built-in-potential in heterostructures induced by X-ray irradiation

Influence of the X-ray irradiation (λ = 0.056 nm) on photoelectric parameters of intrinsic oxide-p-InSe heterojunctions (HJ) and p–n-InSe homojunctions is established. This effect is manifested in an increase of the potential barrier between the contacting semiconductors. It is shown that with increasing irradiation exposure time the barrier value approaches its maximum possible value – one half of the energy gap of the base material.Current–voltage (I–V) and spectral characteristics of the prepared heterostructures are investigated before and after X-ray irradiation. The diode factor of the I–V characteristics for the HJ increases with increasing irradiation time. This increase corresponds to growing contribution of recombination processes in charge transfer mechanisms through the potential barrier. The normalized photocurrent spectra of the p–n-InSe HJ do not show any changes after irradiation. In the spectra of the oxide-InSe structures an insignificantly reduction of photocurrent quantum efficiency is observed only in the short-wave region. The obtained results are interpreted in the framework of the electrostatic model of the formation of radiation defects in crystal lattice.