Since transition metal dichalcogenide (TMD) semiconductors are found as two-dimensional van der Waals materials with a discrete energy bandgap, many TMD based field effect transistors (FETs) are reported as prototype devices. However, overall reports indicate that threshold voltage (V th) of those FETs are located far away from 0 V whether the channel is p- or n-type. This definitely causes high switching voltage and unintended OFF-state leakage current. Here, a facile way to simultaneously modulate the V th of both p- and n-channel FETs with TMDs is reported. The deposition of various organic small molecules on the channel results in charge transfer between the organic molecule and TMD channels. Especially, HAT-CN molecule is found to ideally work for both p- and n-channels, shifting their V th toward 0 V concurrently. As a proof of concept, a complementary metal oxide semiconductor (CMOS) inverter with p-MoTe2 and n-MoS2 channels shows superior voltage gain and minimal power consumption after HAT-CN deposition, compared to its initial performance. When the same TMD FETs of the CMOS structure are integrated into an OLED pixel circuit for ambipolar switching, the circuit with HAT-CN film demonstrates complete ON/OFF switching of OLED pixel, which was not switched off without HAT-CN.

Since transition metal dichalcogenide (TMD) semiconductors are found as 2D van der Waals materials with a discrete energy bandgap, many 2D-like thin field effect transistors (FETs) and PN diodes are reported as prototype electrical and optoelectronic devices. As a potential application of display electronics, transparent 2D FET devices are also reported recently. Such transparent 2D FETs are very few in report, yet no p-type channel 2D-like FETs are seen. Here, 2D-like thin transparent p-channel MoTe 2 FETs with oxygen (O 2 ) plasma-induced MoO x /Pt/indium-tin-oxide (ITO) contact are reported for the first time. For source/drain contact, 60 s short O 2 plasma and ultrathin Pt-deposition processes on MoTe 2 surface are sequentially introduced before ITO thin film deposition and patterning. As a result, almost transparent 2D FETs are obtained with a decent mobility of ≈5 cm 2 V −1 s −1 , a high ON/OFF current ratio of ≈10 5 , and 70% transmittance. In particular, for normal MoTe 2 FETs without ITO, O 2 plasma process greatly improves the hole injection efficiency and device mobility (≈60 cm 2 V −1 s −1 ), introducing ultrathin MoO x between Pt source/drain and MoTe 2 . As a final device application, a photovoltaic current modulator, where the transparent FET stably operates as gated by photovoltaic effects, is integrated.

BackgroundAlthough the proportion of the elderly patients with incident end-stage renal disease (ESRD) patients has been increasing in Korea, there has been a lack of information on outcomes of dialysis treatment. This study aimed to assess the survival rate and to elucidate predictors for all-cause mortality among elderly Korean patients initiating dialysis.MethodsWe analyzed 11,301 patients (6,138 men) aged 65 years or older who had initiated dialysis from 2005 to 2008 and had followed up (median, 37.8 months; range, 3–84 months). Baseline demographics, comorbidities and mortality data were obtained using the database from the Health Insurance Review & Assessment Service.ResultsThe unadjusted 5-year survival rate was 37.6% for all elderly dialysis patients, and the rate decreased with increasing age categories; 45.9% (65∼69), 37.5% (70∼74), 28.4% (75∼79), 24.1% (80∼84), and 13.7% (≥85 years). The multivariate Cox proportional hazard model revealed that age, sex, dialysis modality, the type of insurance, and comorbidities such as diabetes mellitus, myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, hemiparesis, liver disease, and any malignancy were independent predictors for mortality. In addition, survival rate was significantly higher in patients on hemodialysis compared to patients on peritoneal dialysis during the whole follow-up period in the intention-to-treat analysis.ConclusionsSurvival rate was significantly associated with age, sex, and various comorbidities in Korean elderly patients initiating dialysis. The results of our study can help to provide relevant guidance on the individualization strategy in elderly ESRD patients requiring dialysis.

p-and n-channel FETs, homogeneous and heterogeneous complementary metal oxide semiconductor (CMOS) inverters have been reported. [15][16][17][18][19][20] Moreover, PN junction-and Schottky junction-based FETs were even reported using 2D TMD semiconductors. [21,22] However, in a practical view, devices based on only 2D materials are not easy to fabricate and seldom reproducible. Very recently, researchers have attempted other approaches combining 2D materials and conventionally proven ones to fabricate more practical type of classical devices such as CMOS inverters and hetero PN junction diodes. [23][24][25][26][27][28][29][30][31][32] Those could be regarded as practical approaches in consideration that one could use conventionally proven semiconductors for functional electron devices. However, such approaches are still very rare.In the present study, we approach to combine 2D n-/or p-TMD FET and conventional InGaZnO (IGZO) FET, presenting advanced non-classical functions: multivalue (MV) FETs for logic and photodetecting function, and signal frequency doubler. Multivalue logic would be important in the future for minimizing the power consumption which emerges as challenging issues in the present Si-based binary logic circuitry. [33][34][35] Frequency doubling is also an interesting and beneficial technique in alternating current (AC) circuit. [36,37] For these purposes, we have initially fabricated n-IGZO channel FET on glass substrate, which is followed by n-channel TMD (n-ReSe 2 , n-WSe 2 , p-, or ambipolar-MoTe 2 ) FETs. Although top-MoTe 2 /bottom-IGZO combination approach was once introduced for basic classical devices, [26] present study displays more advanced novel functions based on unique device architecture; we use a long and unique-shape gate pattern, so that n-or p-channel TMD and n-IGZO channels may be located side by side sharing a gate metal in common. Atomic layer deposited (ALD) Al 2 O 3 dielectric is located on the patterned gate. According to individual transfer characteristics of two FET devices, our n-IGZO FET always shows higher drain current (I D ) and more positive-side turn-on voltage (V t ) than those of n-TMD channel FETs. As a result, a combined transfer characteristics presented two-step drain current levels, so that their load-resistance inverter might demonstrate three value output Various functions are introduced from a unique field-effect device structure which combines or merges transition metal dichalcogenide (TMD) and InGaZnO (IGZO) channels together on one common gate: multivalue field effect transistors (FETs), photodetecting devices, and signal frequency doublers. Judging by the individual transfer characteristics of two FET devices, the n-IGZO FET always shows higher drain current and more positive-side turn-on voltage than those of n-TMD channel FETs. As a result, a combined transfer characteristic presents two-step drain current levels, so that their load-resistance inverter might demonstrate three value output voltage signals. Those ternary value inverter devices with n...

Among many of 2D semiconductor‐based devices, type III PN junction diodes are given special attentions due to their unique function, negative differential resistance (NDR). However, it has been found uneasy to achieve well‐matched type III PN junctions from 2D–2D van der Waals heterojunctions. Here, the authors present other alternatives of type III heterojunctions, using 2D p‐MoTe2/organic n‐type dipyrazino[2,3‐f:2′,3′‐h]quinoxaline‐2,3,6,7,10,11‐hexacarbonitrile (HAT‐CN) and 2D p‐WSe2/n‐MoOx systems. Those junction diodes appear to well‐demonstrate static and dynamic NDR behavior via resonant tunneling and electron–hole recombination. Extended to an inverter circuit, p‐MoTe2/n‐HAT‐CN diode enables multilevel inverter characteristics as monolithically integrated with p‐MoTe2 channel field effect transistor. The same NDR diode shows dynamic LC oscillation behavior under a constant DC voltage, connected to an external inductor. From p‐WSe2/n‐MoOx oxide diode, similar NDR behavior to those of p‐MoTe2/n‐HAT‐CN is again observed along with LC oscillations. The authors attribute these visible oscillation results to high peak‐to‐valley current ratios of their organic or oxide/2D heterojunction diodes.