An Ultrafast WSe₂Photodiode Based on a Lateral p-i-n Homojunction

TY - JOUR

T1 - An Ultrafast WSe2Photodiode Based on a Lateral p-i-n Homojunction

AU - Zhang, Youwei

AU - Ma, Kankan

AU - Zhao, Chun

AU - Hong, Wei

AU - Nie, Changjiang

AU - Qiu, Zhi Jun

AU - Wang, Shun

N1 - Funding Information: We acknowledge the support from the National Natural Science Foundation of China (12074134 and 61774042), Shenzhen Science and Technology Project (JCYJ20180507183904841), and the Analysis and Testing Center of Huazhong University of Science and Technology. Publisher Copyright: ©

PY - 2021/2/15

Y1 - 2021/2/15

N2 - High-quality homogeneous junctions are of great significance for developing transition metal dichalcogenides (TMDs) based electronic and optoelectronic devices. Here, we demonstrate a lateral p-type/intrinsic/n-type (p-i-n) homojunction based multilayer WSe2 diode. The photodiode is formed through selective doping, more specifically by utilizing self-aligning surface plasma treatment at the contact regions, while keeping the WSe2 channel intrinsic. Electrical measurements of such a diode reveal an ideal rectifying behavior with a current on/off ratio as high as 1.2 × 106 and an ideality factor of 1.14. While operating in the photovoltaic mode, the diode presents an excellent photodetecting performance under 450 nm light illumination, including an open-circuit voltage of 340 mV, a responsivity of 0.1 A W-1, and a specific detectivity of 2.2 × 1013 Jones. Furthermore, benefiting from the lateral p-i-n configuration, the slow photoresponse dynamics including the photocarrier diffusion in undepleted regions and photocarrier trapping/detrapping due to dopants or doping process induced defect states are significantly suppressed. Consequently, a record-breaking response time of 264 ns and a 3 dB bandwidth of 1.9 MHz are realized, compared with the previously reported TMDs based photodetectors. The above-mentioned desirable properties, together with CMOS compatible processes, make this WSe2 p-i-n junction diode promising for future applications in self-powered high-frequency weak signal photodetection.

AB - High-quality homogeneous junctions are of great significance for developing transition metal dichalcogenides (TMDs) based electronic and optoelectronic devices. Here, we demonstrate a lateral p-type/intrinsic/n-type (p-i-n) homojunction based multilayer WSe2 diode. The photodiode is formed through selective doping, more specifically by utilizing self-aligning surface plasma treatment at the contact regions, while keeping the WSe2 channel intrinsic. Electrical measurements of such a diode reveal an ideal rectifying behavior with a current on/off ratio as high as 1.2 × 106 and an ideality factor of 1.14. While operating in the photovoltaic mode, the diode presents an excellent photodetecting performance under 450 nm light illumination, including an open-circuit voltage of 340 mV, a responsivity of 0.1 A W-1, and a specific detectivity of 2.2 × 1013 Jones. Furthermore, benefiting from the lateral p-i-n configuration, the slow photoresponse dynamics including the photocarrier diffusion in undepleted regions and photocarrier trapping/detrapping due to dopants or doping process induced defect states are significantly suppressed. Consequently, a record-breaking response time of 264 ns and a 3 dB bandwidth of 1.9 MHz are realized, compared with the previously reported TMDs based photodetectors. The above-mentioned desirable properties, together with CMOS compatible processes, make this WSe2 p-i-n junction diode promising for future applications in self-powered high-frequency weak signal photodetection.

KW - lateral homojunction

KW - p-i-n diode

KW - photodetector

KW - plasma treatment

KW - selective doping

KW - tungsten diselenide

UR - http://www.scopus.com/inward/record.url?scp=85101512462&partnerID=8YFLogxK

U2 - 10.1021/acsnano.0c08075

DO - 10.1021/acsnano.0c08075

M3 - Article

C2 - 33587610

AN - SCOPUS:85101512462

SN - 1936-0851

VL - 15

SP - 4405

EP - 4415

JO - ACS Nano

JF - ACS Nano

IS - 3

ER -