Charge carrier response time in sputtered a-C/n-Si heterojunctions

Amorphous carbon (a-C)/n-Si heterojunctions were developed by rf magnetron sputtering from a carbon target on Si(100) n-type substrates kept at room temperature. Subsequent metallization by the deposition of sputtered TiN on top of the carbon films resulted in the creation of effective heterojunction devices as shown by electrical characterization. The electrical performance of the devices was further investigated by admittance spectroscopy, allowing the calculation of the charge carrier response time which was found to be of the order of 10−6 s at room temperature, the lower value reported so far when compared to similar values reported for chemically vapor deposited films. These results showed that the devices were suitable for use in fast electronics working in hard environments.