The electrical characterization and response to hydrogen of Schottky diodes with a resistive metal electroderectifying an oversight in Schottky diode investigation

P Dawson (1) , L Feng (1) , L Penate-Quesada (1) , J Mitra (2) , G Hill (3)

1 School of Maths and Physics
2 Physics Department
3 EPSRC National Centre for III-V Technologies

Schottky barrier structures with a resistive metal electrode are examined using the 4-point probe method where the probes are connected to the metal electrode only. The observation of a significant decrease in resistance with increasing temperature (over a range of ~ 100K) in the diode resistance-temperature (R D-T) characteristic is considered due to charge carrier confinement to the metal electrode at low temperature (high resistance), with the semiconductor progressively opening up as a parallel current carrying channel (low resistance) with increasing temperature due to increasing thermionic emission across the barrier. A simple model is constructed, based on thermionic emission at quasi-zero bias, that generates good fits to the experimental data. The negative differential resistance (NDR) region in the R D -T characteristic is a general effect and is demonstrated across a broad temperature range for a variety of Schottky structures grown on Si-, GaAs- and InP- substrates. In addition the NDR effect is harnessed in micro-scaled Pd/n-InP devices for the detection of low levels of hydrogen in an ambient atmosphere of nitrogen.

Mots clés: III-V semicondcutors; palladium; gas sensors; hydrogen 2; Schottky diode; silicon

P Dawson, L Feng, L Penate-Quesada, J Mitra, G Hill. The electrical characterization and response to hydrogen of Schottky diodes with a resistive metal electroderectifying an oversight in Schottky diode investigation. Journal of Physics D: Applied Physics, 2011, 44 (12), pp.125101. ⟨10.1088/0022-3727/44/12/125101⟩. ⟨hal-00604884⟩