Electrical properties of gallium arsenide surfaces and interfaces treated by Ru(3+) ions

The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of Al/n-GaAs and Al/p-GaAs diodes on GaAs substrate treated by Ru3+ ions are investigated and compared with characteristics of GaAs diodes on GaAs untreated substrates. The diodes does not have to show an ideal behaviour of I–V characteristic with an ideality factor of 1.13 and barrier height of 0.85eV and 0.6eV for Al/n-GaAs and Al/p-GaAs diodes respectively. The forward bias saturation current found with a big value (10−10A, 10−12A) in the Al/n-GaAs (untreated) Schottky diodes compared with Al/n-GaAs (treated) diodes. Contrary the forward bias saturation current found with a small value (10−7A, 10−6A) in the Al/p-GaAs (untreated) Schottky diodes compared with Al/p-GaAs (treated) diodes. The energy distribution of interface states was determined from the forward bias I (V) characteristics. The interface states density found large in the Al/GaAs (treated by Ru3+ ions) structure comparing with the Al/GaAs (untreated) structure. In parallel with electrical measurement, the Ru3+ adsorption on treated GaAs surfaces was controlled by photoelectrochemical and electrochemical measurements and by Auger analysis.