I am currently working with a diamond based UV photodetector. I am currently using polycrystalline diamond as a substrate with interdigitated electrodes. Due to the defects and traps of the polydiamond there are some charging effect, which according to literature can take up to days to discharge. Any ideas on how to speed up this process??
Try to warm up the substrate in a dark chamber from a room temperature up to approximately 350C with the speed near 25C/minute. Typically, all the shallow traps / defects will light off the accumulated light sum during this process - which is the accelerated discharge process you are looking for. This is a standard component of the thermo luminescence technique for studying synthetic diamonds.
Thanks Len ! I thought about doing that but I wasn't too sure it would work. Ill try it and come back with the results.
I don't know if this will work w/ polyc-diamond, but Lithium Niobate and Tantalate would also accumulate charge in deep level surface traps that I could discharge in minutes with UV irradiation.what would normallky take overnight. Heat helped, but the UV really did the trick..
Steven. That is a bit odd, as the UV is what excited the carriers to the traps in the first place?
True, UV excited the charges in the diamond in the first place, but the traps were filled under bias (high-field conditions) In both cases, diamond and LiNbO3. The problem is the traps retain the charge after the external bias field is removed, (generating their own fields).
So it seems to me that is all the more reason to expect that the UV will have sufficient energy to dislodge the trapped carriers when the bias is removed, and also deplete the internal field..
NB long-lifetime traps are NOT a problem in materials that have even the tiniest conductivity. Often times, dielectric substrates are purposely doped to provide a waek conduction band to prevent trapping.