Laser induced nano-graphite electrical contacts on synthetic polycrystalline CVD diamond for nuclear radiation detection

We created a radiation detection device from a plate of high quality polycrystalline CVD diamond, fabricating nano-graphite electrical contacts on both diamond surfaces, by front and back irradiation with a 193 nm ArF excimer laser. We measured the electrode electrical resistance and evaluated a graphite resistivity of about 10− 5 Ω ⋅ m. The ohmic nature of the contact graphite/diamond is established measuring the current-voltage characteristic that it is described by a linear behavior up to 90 V, by a Space Charge Limited (SCL) regime above 100 V and below 300 V, and by a Trap Filled Space Charge Limited (TFSCL) regime above 300 V. Finally, we investigated the device response in counting mode to a 60Co γ-rays source and to a 120 GeV proton beam proving its capability to work as a fast nuclear radiation detector.