Gonna try to make betavoltaic

Diamond battery or betavoltaic batteries can be made by having a cell and embbeding a beta emitter with a long lifetime into an anode cathode battery cell.

To create these cells you can us MWCVD to create the diamod coating on an anode, and then

Taken from wikipedia :

A betavoltaic device (betavoltaic cell or betavoltaic battery) is a type of nuclear battery
that generates electric current from beta particles (electrons or positrons) emitted from a 
radioactive source, using semiconductor junctions. A common source used is the hydrogen isotope 
tritium. Unlike most nuclear power sources which use nuclear radiation to generate heat which then 
is used to generate electricity, betavoltaic devices use a non-thermal conversion process, 
converting the electron–hole pairs produced by the ionization trail of beta particles traversing a 
semiconductor.[1]

[1]

Just a quick image of a betavoltic battery taken from standford (http://large.stanford.edu/courses/2013/ph241/harrison2/)

basically what happens here is that you have a beta emitter in a p n junction and you coat a front and back contact.

These can all be plasma coated.

NEXT

also from wikipedia

Researchers at the University of Bristol demonstrated that a large amount of the radioactive 14C was concentrated on the inner walls of the graphite blocks. Due to this, they propose that much of it can be effectively removed from the blocks. This can be done by heating them to the sublimation point of 3,915 K (3,642 °C; 6,587 °F) which will release the carbon in gaseous form. After this, blocks will be less radioactive and possibly easier to dispose of with most of the radioactive 14C having been extracted.[13]

Those researchers propose that this 14C gas could be collected and used to produce man-made diamonds by a process known as chemical vapor deposition using low pressure and elevated temperature, noting that this diamond would be a thin sheet and not of the stereotypical diamond cut. The resulting diamond made of radioactive 14C would still produce beta radiation which researchers claim would allow it to be used as a betavoltaic source. Researchers also claim this diamond would be sandwiched between non-radioactive man-made diamonds made from 12C which would block radiation from the source and would also be used for energy conversion as a diamond semiconductor instead of conventional silicon semiconductors.[13]