Flash memories and semiconductor p-n junctions are two elementary but incompatible building blocks of most electronic and optoelectronic devices. The pressing demand to efficiently transfer massive data between memories and logic circuits, as well as for high data storage capability and device integration density, has fueled the rapid growth of technique and material innovations. Two-dimensional (2D) materials are considered as one of the most promising candidates to solve this challenge. However, a key aspect for 2D materials to build functional devices requires effective and accurate control of the carrier polarity, concentration and spatial distribution in the atomically thin structures. Here, a non-volatile opto-electrical doping approach is demonstrated, which enables reversibly writing spatially resolved doping patterns in the MoTe₂ conductance channel through a MoTe₂/hexagonal boron nitride (h-BN) heterostructure. Based on the doping effect induced by the combination of electrostatic modulation and ultraviolet light illumination, a 3-bit flash memory and various homojunctions on the same MoTe₂/BN heterostructure are successfully developed. The flash memory achieved 8 well distinguished memory states with a maximum on/off ratio over 10⁴. Each state showed negligible decay during the retention time of 2,400 s. The heterostructure also allowed the formation of p-p, n-n, p-n, and n-p homojunctions and the free transition among these states. The MoTe₂ p-n homojunction with a rectification ratio of 10³ exhibited excellent photodetection and photovoltaic performance. Having the memory device and p-n junction built on the same structure makes it possible to bring memory and computational circuit on the same chip, one step further to realize near-memory computing.

Inefficient sample preparation methods hinder the performance of high-throughput single-molecule force spectroscopy (H-SMFS) for viscous damping among reactants and unstable linkage. Here, we demonstrated a sample preparation method for H-SMFS systems to achieve a higher ratio of effective target molecules per sample cell by gas-phase silanization and reactant hydrophobization. Digital holographic centrifugal force microscopy (DH-CFM) was used to verify its performance. The experimental result indicated that the DNA stretching success ratio was improved from 0.89% to 13.5%. This enhanced efficiency preparation method has potential application for force-based DNA stretching experiments and other modifying procedures.