Optical and electronic properties of freestanding single crystal CVD diamond

摘要

We have used photocurrent spectroscopy to detect low concentrations of defects in high optical quality type lla single crystal CVD diamond layers. The main bulk defect in the nominally undoped, type lla single crystal CVD diamond film comes from residual nitrogen in deposition chamber during diamond growth. From the photoionization spectrum in visible and near UV region we extrapolate that the 1 ppb (10~(14) cm~(-3)) nitrogen can be readily detected. For successful production of electronic grade material, the reduction of the residual nitrogen content below 1 ppb level is important. Another set of defect states appears in the near IR region below the onset of the nitrogen related photoionization. These relatively shallow defects may be hydrogen related and can be detected by our novel AMFTPS method.