Thickness‐Dependent, Gate‐Tunable Rectification and Highly Sensitive Photovoltaic Behavior of Heterostructured GeSe/WS2 p–n Diode

• DOI: 10.1002/admi.202000893
• Publication Date: 2020-10-14T05:58:15Z
• Authors: Syed Hassan Abbas...; Junghwan Kim; Ghulam Dastgeer; Muhammad Hussain; Asif Ali; Sajjad Hussain; Jonghwa Eom; Suklyun Hong; Jongwan Jung
• Keywords: 01 natural sciences; 7. Clean energy; 0104 chemical sciences

AbstractThe p–n heterojunction fabricated by the vertical stacking of 2D materials is highly relevant to modern electronics and optoelectronic devices. This research reports a novel p‐GeSe/n‐WS2 heterostructured diode exhibiting prominent thickness‐dependent and gate‐tunable rectification behavior. The rectification ratio increases as the thickness of WS2 is increased. A rectification ratio of 104 is achieved by successfully sweeping the back‐gate voltage. The modulation in the rectification behavior is ascribed to the interlayer electron‐hole recombination. Density functional theory (DFT) calculations further support the thickness‐dependent, gate‐modulated experimental results. The diode exhibits efficient photodetection with promising figures of merit. The photoresponse is investigated under the illuminations of λ equal to 365, 530, and 850 nm. The diode displays a high responsivity of 845 mA W−1 at 850 nm. In addition, the diode exhibits a detectivity of 3.28 × 108 Jones, normalized photocurrent to dark current ratio (NPDR) of 1 × 108 W−1, noise equivalent power (NEP) of 1.9 × 10−12 WHz−1/2, and a rise time of 10 ms. The p‐GeSe/n‐WS2 diode demonstrates excellent rectification and optoelectronic characteristics.