Broadband InSb/Si heterojunction photodetector with graphene transparent electrode.

Silicon-based Schottky heterojunction photodetectors are promising due to its compatibility with semiconductor process. However, the applications of these devices are usually limited to wavelength shorter than 1.1 microm due to the low absorption of electrode materials at infrared. In this report, silicon-based compound semiconductor heterojunction photodetectors with graphene transparent electrode are fabricated. Due to the high absorption of InSb at infrared, as well as the good transparency and excellent electrical conductivity of the graphene, as-prepared photodetector show broadband photoresponse with high performance which includes a specific detectivity of 1.9x1012 cm Hz1/2/W, responsivity of 132 mA/W, on/off ratio of 1x105, rise time of 2 micros, 3dB cut-off frequency of 172 KHz and response wavelength covering 635 nm, 1.55 microm and 2.7 microm. This report proved that graphene as transparent electrode has a great effect on the performance improvement of the silicon-based compound semiconductor heterojunction photodetectors.