This paper describes a novel nanofluidic phenomenon where untethered DNA and chromatin are linearized by rapidly narrowing an elastomeric nanochannel filled with solutions of the biopolymers. This nanoscale squeezing procedure generates hydrodynamic flows while also confining the biopolymers into smaller and smaller volumes. The unique features of this technique enable full linearization then trapping of biopolymers such as DNA. The versatility of the method is also demonstrated by analysis of chromatin stretchability and mapping of histone states using single strands of chromatin.

While the formation of cracks is often stochastic and considered undesirable, controlled fracture would enable rapid and low cost manufacture of micro/nanostructures. Here, we report a propagation-controlled technique to guide fracture of thin films supported on soft substrates to create crack arrays with highly controlled periodicity. Precision crack patterns are obtained by the use of strategically positioned stress-focusing V-notch features under conditions of slow application of strain to a degree where the notch features and intrinsic crack spacing match. This simple but robust approach provides a variety of precisely spaced crack arrays on both flat and curved surfaces. The general principles are applicable to a wide variety of multi-layered materials systems because the method does not require the careful control of defects associated with initiation-controlled approaches. There are also no intrinsic limitations on the area over which such patterning can be performed opening the way for large area micro/nano-manufacturing.

In this paper, we present a room-temperature electroluminescence (EL) study of amorphous nonstoichiometric silicon nitride (SiNX) films. The light-emitting device is formed by an ITO/SiNX/p-type silicon structure. EL shows a yellowish broad emission spectrum with a power efficiency of 10−6. The EL peak energy depends on the bias voltage rather than on the silicon content in SiNX. By fitting the current-voltage characteristic with existing models, we found that under high voltages the Poole–Frenkel hole conduction is the main carrier transport mechanism in these devices. Injected electrons are captured by silicon dangling bonds (K center) and recombine with holes, which are localized in valence band tail states. Unbalanced hole and electron injection and nonradiative recombination are the main constraints on the EL efficiency of SiNX.

An electrically pumped ZnO homojunction random laser diode based on nitrogen‐doped p‐type ZnO nanowires is reported. Nitrogen‐doped ZnO nanowires are grown on a ZnO thin film on a silicon substrate by chemical vapor deposition without using any metal catalyst. The p‐type behavior is studied by output characteristics and transfer characteristic of the nanowire back‐gated field‐effect transistor, as well as low‐temperature photoluminescence. The formation of the p–n junction is confirmed by the current–voltage characteristic and electron beam‐induced current. The nanowire/thin‐film p–n junction acts as random laser diode. The random lasing behavior is demonstrated by using both optical pumping and electrical pumping, with thresholds of 300 kW/cm2 and 40 mA, respectively. The angle‐dependant electroluminescence of the device further proves the random lasing mechanism. An output power of 70 nW is measured at a drive current of 70 mA.