Tunnelling current in Schottky diodes containing InAs quantum dots

Abstract

Current transport mechanism in Schottky diode containing InAs quantum dots (QDs) is investigated using temperature-varying current–voltage characteristics. We found that the tunnelling emission has obvious effects on the I–V characteristics. The I–V–T measurements revealed clear effects of QDs on the overall current flow. Field emission (FE, pure tunnelling effect) was observed at low temperature and low voltages bias region. The zero-bias barrier height decreases and the ideality factor increases with decreasing temperature, and the ideality factor was found to follow the T0-effect. When the reverse bias is varied, the ideality factors of Schottky barriers exhibit oscillations due to the tunnelling of electrons through discrete levels in quantum dots. The traps distributed within InAlAs layer can also act as a transition step for reverse bias defect-assisted tunnelling current which can phenomenologically explain the decrease of the effective barrier height with measurement temperature.