Ultrahigh-performance inverters based on CdS nanobelts.
ABSTRACT We report ultrahigh-performance inverters, each consisting of two top-gate metal-oxide-semiconductor field-effect transistors based on n-CdS nanobelts. High-kappa HfO(2) dielectrics are used as the top-gate oxide layers. The inverters have a large supply voltage (V(DD)) range (from 50 mV to 10 V) and very high voltage gain ( approximately 10, 100, and 1000 at V(DD) = 0.2, 1, and 10 V, respectively). Current consumption is less than 7 nA at V(DD) = 1 V, corresponding to a power consumption of less than 7 nW. The high and low output voltages are close to full rail. The inverters also exhibit good dynamic behavior with square wave input at frequencies up to 1 kHz. The operation of the inverters is analyzed in detail. The inverters are promising for future low power high performance logic circuit applications.
[show abstract] [hide abstract]
ABSTRACT: Although possible non-homogeneous strain effects in semiconductors have been investigated for over a half century and the strain-gradient can be over 1% per micrometer in flexible nanostructures, we still lack an understanding of their influence on energy bands. Here we conduct a systematic cathodoluminescence spectroscopy study of the strain-gradient induced exciton energy shift in elastically curved CdS nanowires at low temperature, and find that the red-shift of the exciton energy in the curved nanowires is proportional to the strain-gradient, an index of lattice distortion. Density functional calculations show the same trend of band gap reduction in curved nanostructures and reveal the underlying mechanism. The significant linear strain-gradient effect on the band gap of semiconductors should shed new light on ways to tune optical-electronic properties in nanoelectronics. KeywordsStrain-gradient effect–CdS nanowire–bending deformation–cathodoluminescenceNano Research 04/2012; 4(3):308-314. · 6.97 Impact Factor