Behavioral Contrast of Electron and Hole Transport in High-Resolution Diamond Detectors: A Biparametric Correlation Study

In this letter we investigate for the first time the behavioral differences of transport properties of electrons and holes observed in high-resolution radiation detectors fabricated on high-purity single crystalline diamond using biparametric (BP) correlation studies. The chemical vapor deposition (CVD) grown 500 μm thick diamonds exhibited an excellent energy resolution of 0.5% for 5486 keV alpha particles for both electron and hole transport in a vertical electrode geometry. Interestingly, the behavior of the electron and hole transport were found to be vastly different at bias voltages less than 100 V. No discernable detector signal was observed due to electron transit below an applied bias of -100 V. The hole transit on the other hand, resulted in resolvable pulse height spectrum (PHS) from bias voltages as low as +10 V. Digital biparametric correlation studies of the rise-times and induced charge from each interaction of the incident alpha particles, revealed that the observed difference is due to the excessive electron trapping below bias voltages of -100 V. At lower biases, the width of the alpha peak in the PHS due to hole movement, was hardly affected by trapping and was observed to be limited due to lower hole drift velocities. The developed method with new insights of correlating the biparametric plots and the detector performance can be extended to vast range of semiconductor detectors.