Self-aligned growth of CdTe photodetectors using a graphene seed layer

We demonstrate the self-aligned growth of CdTe photodetectors using graphene as a pre-defined seed layer. Defects were generated in the graphene prior to growth to act as CdTe nucleation sites. Self-aligned CdTe structures were grown selectively on the pre-defined graphene region. The electrical and optoelectrical properties of the photodetectors were systematically analyzed. Our CdTe devices displayed Ohmic behavior with a low sheet resistance of 1.24 x 10(8) Omega/sq. Excellent photodetecting performances were achieved, including a high on-off ratio (similar to 2.8), fast response time (10.4 s), and highly reproducible photoresponses. The fabrication method proposed here for these self-aligned device structures proves valuable for the development of next-generation graphene-semiconductor hybrid devices. (C) 2015 Optical Society of America