Analyzing the mechanism of hydrogen adsorption effects on diamond based MIS hydrogen sensors

The current conduction mechanism and the change in device parameters of diamond based MIS hydrogen sensor upon hydrogen adsorption is investigated over the temperature range of 27-100 degrees C. The current conduction mechanism of the diamond based hydrogen sensitive MIS diode in the forward-bias region is found to be space charge limited in air and hydrogen environments. The space charge limited current (SCLC) conduction mechanism is characterized by an ohmic region at low bias voltage and a power law dependency of voltage (I similar to V-n with n greater than or equal to 2) at higher voltage range. The space charge limited current (SCLC) conduction mechanism prohibits the use of conventional methods to determine the device parameters. This paper presents a method to determine device parameters such as the ideality factor, n, barrier height, phi(B), and tunneling factor, a chi(1/2)delta, and explain the change in these parameters upon H-2 adsorption.