Two-dimensional non-volatile programmable p–n junctions

Abstract

Semiconductor p-n junctions are the elementary building blocks of most electronic and optoelectronic devices. The need for their miniaturization has fuelled the rapid growth of interest in two-dimensional (2D) materials. However, the performance of a p-n junction considerably degrades as its thickness approaches a few nanometres and traditional technologies, such as doping and implantation, become invalid at the nanoscale. Here we report stable non-volatile programmable p-n junctions fabricated from the vertically stacked all-2D semiconductor/insulator/metal layers (WSe/hexagonal boron nitride/graphene) in a semifloating gate field-effect transistor configuration. The junction exhibits a good rectifying behaviour with a rectification ratio of 10 and photovoltaic properties with a power conversion efficiency up to 4.1% under a 6.8 nW light. Based on the non-volatile programmable properties controlled by gate voltages, the 2D p-n junctions have been exploited for various electronic and optoelectronic applications, such as memories, photovoltaics, logic rectifiers and logic optoelectronic circuits.

The ambipolar transport behavior of WSe2 transistors and its analogue circuits

“…Although layered black phosphate has been shown to possess a unique ambipolar property 7 , it hardly survives after several hours of exposure in the atmosphere due to the low reactive barrier between black phosphate and oxygen/water [8][9][10] . Recently, transition metal dichalcogenides (MX 2 , where M = group IVB-VIIB metal and X = chalcogen) with a layered crystal structure were demonstrated to exhibit excellent semiconducting electrical properties with a large on/off ratio [11][12][13][14] . Among them, tungsten diselenide (WSe 2 ), which consists of one layer of W atoms sandwiched between two layers of Se atoms, has many excellent properties providing potential applications, including valley-based electronics 15,16 , spin-electronics, and optoelectronics 17,18 .…”

Recent Advances in Black Phosphorus‐Based Electronic Devices

“…[52,55,59] Compared with other 2D materials, for instance, MoS 2 , BP has the advantage of ambipolar transport characteristics. [52,55,59] Compared with other 2D materials, for instance, MoS 2 , BP has the advantage of ambipolar transport characteristics.…”

“…[52] By virtue of the ambipolar characteristic of BP, both electrons and holes can be stored in the MoS 2 layer by gate modulation, which enables the development of type-switching memories and reconfigurable logic circuits with high-performance. [59] As shown in Figure 6e, the three different 2D nanoflakes are vertically stacked together. By applying different back-gate bias, the polarities of carriers inside the BP channel can be reversibly switched, leading to interchangeable high and low current levels of the erased and programmed states of the device.…”

Nanogap‐Engineerable Electromechanical System for Ultralow Power Memory

“…Continuation of Moore's law to the sub‐10‐nm scale requires the development of new technologies for creating electrode nanogaps, in architectures which allow a third electrostatic gate 1, 2, 3, 4. Nanogap engineering of low‐dimensional nanomaterials has the potential to fulfill this need, provided their structures and properties at the moment of gap formation could be controlled, which has been of emerging interest in a variety of fields, ranging from molecular electronics to memories 2, 5, 6, 7, 8, 9, 10.…”