In-situ preparation of 1T’-MoTe2/pyramidal-Si mixed van der Waals heterojunction toward high performance photodetection

1T’-MoTe 2 /flat-Si and 1T’-MoTe 2 /pyramidal-Si heterojunction photodetectors were in-situ fabricated. • The MoTe 2 /pyramidal-Si heterojunction photodetector exhibits 31% enhancement in responsivity compared with the MoTe 2 /flat-Si counterpart. • The MoTe 2 /pyramidal-Si heterojunction photodetector exhibits broadband spectral response (400-1550 nm), high responsivity (451 mA/W), high specific detectivity (7.8 × 10 11 Jones), and fast response (4 μs). • An 8 × 8 photodetector array is fabricated and demonstrates good imaging capability. Mixed van der Waals (vdW) heterojunction photodetectors have attracted considerable attention in recent years due to synergistic effects of component materials with different dimensions, which enable enhanced performance. Among these mixed vdW heterojunctions, two-dimensional (2D) material/Si heterojunction photodetectors hold great promise, combining the superior optoelectronic properties of 2D materials with the mature processing technology of Si. In this work, we report the fabrication of a 1 T′-MoTe 2 /pyramidal-Si heterojunction photodetector via sputtering and subsequent in-situ thermal conversion. Compared with the MoTe 2 /flat-Si counterpart, the MoTe 2 /pyramidal-Si photodetector shows a 31% enhancement in responsivity, reaching 451 mA/W at 820 nm. In addition, it exhibits excellent photodetection performance in terms of specific detectivity (7.8 × 10 11 Jones at 850 nm under zero bias), broadband spectral response (400–1550 nm), large linear dynamic range (162 dB), and fast response (4 μs at 850 nm under a bias voltage of −5 V). An 8 × 8 photodetector array is fabricated and demonstrates good imaging capability. Our work provides a novel approach for developing high-performance mixed vdW heterojunction photodetectors. Download: Download high-res image (207KB) Download: Download full-size image