Enhancing the Diode Characteristics of Pulsed Laser-Deposited n-MgxZn1-xO/p-Si Heterojunction: Role of Oxygen Ambient Pressure

Herein, diode characteristics of n-MgxZn1-xO/p-Si heterojunctions grown by pulsed laser deposition at different oxygen ambient pressures are investigated. It is found that the heterojunctions grown at lower oxygen growth pressure of 1.0 x 10(-2) mbar and below do not show rectifying diode-like behavior, whereas those grown at higher oxygen pressures at and above 2.5 x 10(-2) mbar exhibit perfect diode-like rectifying characteristics. The diode characteristics are found to improve significantly with increasing oxygen ambient pressure during the growth of MgxZn1-xO film. The current-voltage measurements show that the n-MgxZn1-xO/p-Si heterojunction diode grown at a higher oxygen ambient pressure of approximate to 1.0 x 10(-1) mbar has the lowest reverse saturation current of approximate to 19 nA and highest rectification ratio of approximate to 1.4 x 10(4). The capacitance-voltage measurements reveal that the depletion layer width of heterojunction diodes increases manifold with increasing oxygen ambient pressure during the growth of MgxZn1-xO, which is understood in terms of decrease in carrier concentrations in the MgxZn1-xO thin films grown at higher oxygen ambient pressures. The n-MgxZn1-xO/p-Si heterojunction diodes, grown at high oxygen ambient pressures, with low reverse saturation current, high rectification ratio, and large depletion width may have potential application in wide-bandgap nanoelectronic devices and UV enhanced photodetectors.