February 01, 2017

Mask effect in nano-selective-area-growth by MOCVD on thickness enhancement, indium incorporation, and emission of InGaN nanostructures on AlN-buffered Si(111) substrates

  • Bonanno P.
  • Decobert J.
  • El Gmili Y.
  • Li X.
  • Ougazzaden A.
  • Patriarche G.
  • Pradalier C.
  • Puybaret R.
  • Salvestrini J.
  • Sundaram S.
  • Voss P.

In this paper, we studied the effect of temperature and mask margin size on optical emission and growth rate enhancement (GRE) of InGaN grown by metal organic chemical vapor deposition (MOCVD) and nano-selective-area growth (NSAG) on AlN-buffered Si(111). For all mask geometries and temperatures, NSAG produced 90% single-crystal InGaN nanopyramids with smooth facets, perfect selectivity, and 1.2 times the indium composition enhancement (23% and 33% for 800 degrees C and 780 degrees C NSAG, respectively) as found in non-NSAG planar growth at the same conditions. The vapor phase diffusion model was found to be insufficient to predict NSAG GRE, and we propose an explanation combining mechanisms from the vapor phase diffusion with surface migration models. A two-peak emission was noted for all NSAG. The total and relative intensities of the two peaks was found to be strongly dependent upon both temperature and local indium precursor concentration during growth, the latter of which varies based on mask margin size. In NSAG grown at lower temperature and with higher local indium precursor concentration, the bluer of the two peaks was more dominant and the overall emission intensity was higher. InGaN nanopyramids were chemically uniform, ruling out phase separation as origin of the double-peak. We propose an explanation based on the sudden transition from strained to relaxed growth moderated by temperature and local indium precursor concentration. (C) 2017 Optical Society of America

View Original Article

Recent Publications

August 09, 2017

A Cloud Native Approach to 5G Network Slicing

  • Francini A.
  • Miller R.
  • Sharma S.

5G networks will have to support a set of very diverse and often extreme requirements. Network slicing offers an effective way to unlock the full potential of 5G networks and meet those requirements on a shared network infrastructure. This paper presents a cloud native approach to network slicing. The cloud ...

August 01, 2017

Modeling and simulation of RSOA with a dual-electrode configuration

  • De Valicourt G.
  • Liu Z.
  • Violas M.
  • Wang H.
  • Wu Q.

Based on the physical model of a bulk reflective semiconductor optical amplifier (RSOA) used as a modulator in radio over fiber (RoF) links, the distributions of carrier density, signal photon density, and amplified spontaneous emission photon density are demonstrated. One of limits in the use of RSOA is the lower ...

July 12, 2017

PrivApprox: Privacy-Preserving Stream Analytics

  • Chen R.
  • Christof Fetzer
  • Le D.
  • Martin Beck
  • Pramod Bhatotia
  • Thorsten Strufe

How to preserve users' privacy while supporting high-utility analytics for low-latency stream processing? To answer this question: we describe the design, implementation and evaluation of PRIVAPPROX, a data analytics system for privacy-preserving stream processing. PRIVAPPROX provides three properties: (i) Privacy: zero-knowledge privacy (ezk) guarantees for users, a privacy bound tighter ...