Articles you may be interested inCoplanar amorphous-indium-gallium-zinc-oxide thin film transistor with He plasma treated heavily doped layer Appl. Phys. Lett.Highest transmittance and high-mobility amorphous indium gallium zinc oxide films on flexible substrate by roomtemperature deposition and post-deposition anneals Appl. Phys. Lett. 99, 051901 (2011); 10.1063/1.3619196 Role of order and disorder on the electronic performances of oxide semiconductor thin film transistorsWe investigated the amorphous region of the In 2 O 3 -ZnO material system. The composition dependence of the amorphous region was explored and the films exhibited an n-type semiconductor behavior with low resistivities in the range of 4 ϫ 10 −4 -6.33ϫ 10 −4 ⍀cm. These amorphous films have a very wide transmittance window range of 300-2500 nm, and the transmittance is higher than 85% in the fiber-optics telecommunication window of 1.30-1.55 m. The band gap of amorphous films can be engineered from 2.66 to 3.05 eV, by varying the zinc/ ͑zinc+ indium͒ atomic ratio. A monotonous decrease in mobility from 71.6 to 59.4 cm 2 / V s was observed with an increase in zinc/ ͑zinc+ indium͒ atomic ratio from 0.19 to 0.43 in the amorphous region. This trend was explained on the basis of percolation theory and overlap integral calculations. The effective mass of these amorphous films was calculated using the Drude model in the free-carrier absorption region and correlated with composition as well as the carrier concentration of the films.

We have investigated plasma-induced damage of the inductively coupled plasma (ICP) etched surface of n-type GaN using Cl2/BCl3 chemistry. The surface morphology of the etched GaN under different plasma conditions is analyzed by atomic force microscopy. X-ray photoelectron spectroscopy is used to correlate the chemical changes induced by plasma etching of the GaN surface. We have carried out photoluminescence measurements of etched GaN surfaces subjected to varying ICP conditions. The intensity of the band-edge and yellow luminescence transitions was used to evaluate the damage introduced into the semiconductor during dry etching.

Nanoscale all-optical circuits driven by optical forces have broad applications in future communication, computation, and sensing systems. Because human society faces huge challenges of energy saving and emission reduction, it is very important to develop energy-efficient nano-optomechanical devices. Due to their high quality (Q) factors, resonance modes of cavities are capable of generating much larger forces than waveguide modes. Here we experimentally demonstrate the use of resonance modes of double-coupled one-dimensional photonic crystal cavities to generate bipolar optical forces. Attractive and repulsive forces of -6.2 nN and 1.9 nN were obtained with respective launching powers of 0.81 mW and 0.87 mW in the waveguide just before cavities. Supported by flexible nanosprings (spring constant 0.166 N/m), one cavity is pulled to (pushed away from) the other cavity by 37.1 nm (11.4 nm). The shifts of the selected resonance modes of the device are mechanically and thermally calibrated with an integrated nanoelectromechanical system actuator and a temperature-controlled testing platform respectively. Based on these experimentally-obtained relations, probe mode shifts due to the optomechanical effect are decoupled from those due to the thermo-optic effect. Actuated by the third-order even pump mode, the optomechanical shift of the second-order even probe mode is found to be about 2.5 times its thermal shift, indicating a highly efficient conversion of light energy to mechanical energy.

In this Letter, we report an approach to experimentally determine the optomechanical coupling coefficient of coupled cavities, taking advantage of the ultra-fine cavity positioning capability of a nanoelectromechanical system (NEMS) actuator design. The approach is simple and flexible and can measure the optomechanical coupling coefficient as a function of the coupled cavities' slot gap. In addition, the ratio of mechanical detunings of the odd and even resonance modes can make the existing approach to the decoupling of thermo-optic and optomechanical effects more precise and applicable to more types of cavities.

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Articles you may be interested inEffect of annealing on metastable shallow acceptors in Mg-doped GaN layers grown on GaN substrates Appl. Phys. Lett. 92, 151904 (2008); 10.1063/1.2909541Desorption of InSb(001) native oxide and surface smoothing induced by low temperature annealing under molecular hydrogen flowWe report a systematic study of the effects of wet chemical treatment, inductively coupled plasma etching, and thermal annealing on the surface and optical properties of Mg-doped p-type GaN. The chemical bonding and surface stoichiometry of the GaN surface subjected to different processing steps are analyzed based on the results of x-ray photoelectron spectroscopy. Atomic force microscopy has been employed to characterize the surface morphology. Photoluminescence ͑PL͒ and micro-Raman techniques have been used to investigate the electronic and vibrational properties of plasma etched surface. We have correlated the surface changes induced by dry etching of p-type GaN to the corresponding changes in the defect and impurity related states, through their manifestation in the PL spectra. We have observed several local vibrational modes ͑LVMs͒ in p-type GaN subjected to various processing steps. A broad structure in the low-temperature Raman spectra around 865 cm Ϫ1 is attributed to the electronic Raman scattering from neutral Mg acceptors. In addition to the LVMs of Mg-H n complexes, two new modes near 2405 and 2584 cm Ϫ1 are observed from the etched p-GaN surface. We have also carried out PL and micro-Raman analyses of Mg-doped GaN films annealed under different conditions.

InSbN p-n junctions prepared by N + and Mg + implantation into InSb wafers for long wavelength infrared photodetection are demonstrated for the first time. The detection wavelength can be controlled by monitoring the implanted nitrogen. The measured peak wavelengths are consistent with the bandgaps of the alloys calculated using a 10-band k . p model based on In-N bond.Introduction: It is well known that GaAs-based quantum well structures and HgCdTe-based photodiodes are widely used for long wavelength photodetections [1,2]. Recently, InSbN alloys have attracted great interest owing to their importance in fundamental research and potential applications for long wavelength photodetection [3][4][5][6]. Murdin et al. have reported that the Auger recombination rate in the InSbN alloy is only about one third of that of the equivalent bandgap HgCdTe using a time-resolved pump-probe technique [3]. They have also confirmed the increasing of electron effective mass in the alloys by cyclotron resonance [4]. Veal et al. have presented experimental evidence of a negative bandgap in a thin layer of InSbN fabricated by low energy N implantation using high-resolution electron-energy-loss spectroscopy [5]. As far as device application is concerned, there is no report on InSbN-based photodiodes for photodetection of mid to long wavelength infrared radiation. In this Letter, we report for the first time the successful fabrication of an InSbN p-n junction photodiode by direct N + and Mg + implantation into InSb wafers and demonstration of significant photo-response in the long wavelength infrared range.

A systematic study of the etching of InP material by hydrogen bromide (HBr)-based chemistry is conducted using the inductively coupled plasma (ICP) technique. Sidewall profiles, material selectivity, surface morphologies, and the residual species due to the chemistry are observed as functions of varying process parameters like ICP power, reactive ion etching (RIE) power and pressure. The highest selectivity of InP:PR of 4.2 is achieved at an ICP power of 100 W for a constant set of RIE power, pressure, HBr flow rate, and temperature parameters. Sidewall striations on etched faces have been eliminated by optimizing baking parameters on the photoresist pattern prior to etching. A characteristic kink effect phenomenon is observed with the introduction of argon in HBr chemistry to which is attributed the fluctuation of the chamber pressure. X-ray photoelectron spectroscopy results indicate the strong presence of InBr x , which is believed to affect the formation of anisotropic sidewalls at room temperature. © 2004 The Electrochemical Society. All rights reserved.