No abstract

Memory cells have always been an important element of information technology. With emerging technologies like big data and cloud computing, the scale and complexity of data storage has reached an unprecedented peak with a much higher requirement for memory technology. As is well known, better data storage is mostly achieved by miniaturization. However, as the size of the memory device is reduced, a series of problems, such as drain gate‐induced leakage, greatly hinder the performance of memory units. To meet the increasing demands of information technology, novel and high‐performance memory is urgently needed. Fortunately, emerging memory technologies are expected to improve memory performance and drive the information revolution. This review will focus on the progress of several emerging memory technologies, including two‐dimensional material‐based memories, resistance random access memory (RRAM), magnetic random access memory (MRAM), and phase‐change random access memory (PCRAM). Advantages, mechanisms, and applications of these diverse memory technologies will be discussed in this review.

The assessment of the estrogen receptor (ER) alpha and the progesterone receptor (PgR) in breast cancer tissues is important for discriminating between hormone-dependent and hormone-independent tumors. ERbeta, a more recently discovered ER, may influence estrogen action through the ERalpha pathway. To evaluate the clinical significance of these receptors in the response to endocrine therapy, we investigated their expression in primary breast cancer tissues. ERalpha and PgR were evaluated using immunohistochemistry (IHC) and enzyme immunoassay (EIA) and ERbeta expression was determined using IHC and reverse transcription-polymerase chain reaction. When the cut-off level of EIA was set at 13 fmol/mg protein for ERalpha and that for IHC was set as an IHC score between 2 and 3, a significant correlation between ERalpha EIA and IHC was seen (concordance rate 88.4%). This indicates that this cut-off level of ERalpha IHC can be adopted to quantify breast cancer prognoses. Furthermore, the tumors with positive expression of ERalpha IHC or PgR IHC using this criterion were significantly related to the response to endocrine therapy. Additionally, tumors with positive expression of ERbeta wild-type tended to have a better response to endocrine therapy than negative ones, and tamoxifen responders tended to exhibit a lower ratio of ERbetacx (one of the ERbeta variants) to ERbeta wild-type than nonresponders. The results concerning ERbeta are not yet fully understood; further investigations and evaluations should analyze the role of ERbeta wild-type and variant type in breast cancer treatment.

Uncooled infrared photodetectors have evoked widespread interest in basic research and military manufacturing because of their low‐cost, compact detection systems. However, existing uncooled infrared photodetectors utilize the photothermoelectric effect of infrared radiation operating at 8–12 µm, with a slow response time in the millisecond range. Hence, the exploration of new uncooled mid‐wavelength infrared (MWIR) heterostructures is conducive to the development of ultrafast and high‐performance nano‐optoelectronics. This study explores a van der Waals heterojunction on epitaxial HgCdTe (vdWs‐on‐MCT) as an uncooled MWIR photodetector, which achieves fast response as well as high detectivity for spectral blackbody detection. Specifically, the vdWs‐on‐MCT photodetector has a fast response time of 13 ns (77 MHz), which is approximately an order of magnitude faster than commercial uncooled MCT photovoltaic photodetectors. Importantly, the device exhibits a photoresponsivity of 2.5 A W‐1, quantum efficiency as high as 85%, peak detectivity of 2 × 1010 cm Hz1/2 W‐1 under blackbody radiation at room temperature, and peak detectivity of up to 1011 cm Hz1/2 W‐1 at 77 K. Thereby, this work facilitates the effective design of high‐speed and high‐performance heterojunction uncooled MWIR photodetectors.

With the rapid development of the information age, more and more new technologies such as big data and cloud computing are beginning to emerge. As a result, the demand for high data‐storage density is becoming more and more urgent. In the past 10 years, data‐storage density has been greatly improved by reducing the size of memory cells. However, as semiconductor technology nodes have shrunk, a number of problems have appeared in metal–oxide–semiconductor field‐effect transistor (MOSFET)‐based memory cells, such as gate‐induced drain leakage, drain‐induced barrier lowering, and reliability issues. Fortunately, due to their atomic thickness, high mobility, and sustainable miniaturization properties, 2D atomic crystals (2D materials) are considered the most promising substitute for silicon to solve those issues. This review investigates the use of 2D materials in nonvolatile and volatile memories, including MOSFET‐based memory, magnetic random‐access memory, resistive random‐access memory, dynamic random‐access memory, semi‐floating‐gate memory, and other novel memories.

No abstract

Emerging low-dimensional materials exhibit the potential in realizing next-generation room-temperature blackbody-sensitive infrared detectors. As a narrow band gap semiconductor, low-dimensional tellurium (Te) has been a focus of infrared detector research attention because of its high hole mobility, large absorptivity, and environmental stability. However, it is still a challenge to fabricate blackbody-sensitive Te-based infrared detectors with a low dark current and fast speed. In this work, a heterojunction device based on Te and graphene is constructed, achieving high detectivity and a fast response time from visible to mid-infrared. Specifically, under 2 μm laser irradiation, the heterojunction photodetector exhibits a detectivity of 1.04 × 10 9 cm Hz 1/2 W −1 , a fast response time of 28 μs, and good ambient stability. Moreover, the photodetector demonstrates a room-temperature blackbody sensitivity with the peak detectivity of up to 3.69 × 10 8 cm Hz 1/2 W −1 under zero bias. Linear array devices are further explored and show good performance uniformity for potential imaging applications. Our work demonstrates that the Te/graphene heterojunction detector will be one of the competitive candidates for next-generation uncooled blackbody-sensitive infrared photodetectors.

Graphene, a member of layered two-dimensional (2D) materials, possesses high carrier mobility, mechanical flexibility, and optical transparency, as well as enjoying a wide range of promising applications in electronics. Adopting the chemical vaporization deposition method, the majority of investigators have ubiquitously grown single layer graphene (SLG), which inevitably involves polycrystalline properties. Here we demonstrate a simple method for the direct visualization of arbitrarily large-size SLG domains by synthesizing one-hundred-nm-scale MoS single crystals via a high-vacuum molecular beam epitaxy process. The present study based on epitaxial growth provides a guide for probing the grain boundaries of various 2D materials and implements higher potentials for the next-generation electronic devices.