Potential Distributions in Metal-Semiconductor and p-i-n Structures on a-Si:H by Capacitive Techniques

C(Q)-f and C-V-f characteristics have been used to find the barrier profile and depletion width in several Schottky (i-n+) structures on a-Si:H. Depletion widths for Pd and Cr Schottky structures are estimated to be around 0.28 and 0.21 μm, respectively. Dark C-V measurements on these structures do not show the trends expected from the semiconductor behavior of the I region. Instead, trap controlled current conduction in the I layer fits the dark C-V characteristics. Dark I-V data further support this observation. Trends in the capacitance measurements on p-i-n structures have also been explained on the basis of the above model.