Results are presented for ZnO-based ultraviolet light emitting diodes (LEDs) that employ a BeZnO∕ZnO active layer comprised of seven quantum wells. Arsenic and gallium are used for p-type and n-type layers. The ZnO-based LEDs show two dominant electroluminescence peaks located in the ultraviolet spectral region between 360 and 390nm, as well as a broad peak at 550nm.

A wide-band gap oxide alloy, BeZnO, is proposed and studied in this letter. The BeZnO films were deposited on sapphire substrates by our hybrid beam deposition growth method. The value of the energy band gap of BeZnO can be efficiently engineered to vary from the ZnO band gap ͑3.4 eV͒ to that of BeO ͑10.6 eV͒. BeZnO can be used for fabricating films and heterostructures of ZnO-based electronic and photonic devices and for other applications. Changes in the measured energy band gap and lattice constant values with Be content are described for BeZnO alloys.

Single-mode quantum cascade lasers employing asymmetric Mach-Zehnder interferometer type cavities Appl. Phys. Lett. 101, 161115 (2012) Bistability patterns and nonlinear switching with very high contrast ratio in a 1550nm quantum dash semiconductor laser Appl. Phys. Lett. 101, 161117 (2012) Relative intensity noise of a quantum well transistor laser Appl. Phys. Lett. 101, 151118 (2012) Blue monolithic AlInN-based vertical cavity surface emitting laser diode on free-standing GaN substrate Appl. Phys. Lett. 101, 151113 (2012) Ground state terahertz quantum cascade lasers

The potential use of ZnO-based photonic and electronic devices has been demonstrated by the fabrication of prototype ultraviolet (UV) photodetector and field-effect transistor (FET) devices that contain films of p-type ZnO with arsenic as the p-type dopant. These p-type films have high crystalline quality and show long-term stability. The ZnO UV photodetectors are based on p-n junctions. The FETs are made with metal-semiconductor Schottky contacts on p-type ZnO and are normally off (enhancement) devices. The spectral and electrical characteristics of these devices are presented and explained.

Low-k films with k of 2.5–2.9 were deposited under different conditions of pressures and temperatures using a plasma-enhanced chemical vapor deposition (PECVD) system. These films were prepared using a new liquid precursor, tetravinyltetramethylcyclotetrasiloxane (TVTMCTS) and H2 carrier gas. The rf power was kept as low as possible to maintain the original ring structure in the films. The as-deposited films were annealed and the dielectric and optical properties were investigated. Identification of the absorption bands in the IR spectra for as-deposited films reveals a broadband around 950–1200 cm−1 arising from the Si–O stretching mode of the ring (1065 cm−1) and chain structure (1000 cm−1), respectively; a band at 750–900 cm−1 due to Si–O bending (790 cm−1); Si–CH3 rocking mode (760 cm−1); a sharp band centered at 1260 cm−1 due to a Si–CH3 bending mode; and a broadband at 2800–3000 cm−1 due to the CH group. A comparison of the IR spectra of the PECVD film and TVTMCTS liquid reveals that vinyl vibrations (Si–CH=CH2) at 960, 1410, and 3030–3095 cm−1 for CH2 and at 1598 cm−1 for C=C present in the liquid were not detected in the CVD films. Hence C=C bonds were broken in the plasma polymerization process. As the pressure and the deposition temperature (TD) increased, the intensity of the Si–O vibration arising from the ring structure increased and decreased, respectively. Thus by tuning the pressure and TD we can control the structure of the film. There is a good correlation found between the Si–CH3 and Si–O ring intensities and k values; the increasing Si–CH3 and Si–O ring is accompanied by decreasing k. The films were thermally stable up to 400 °C annealing temperature.