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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Investigation of Quantum Dot Intermixing Technique To Modify Emission Wavelength

Hsu, De-chang 30 July 2008 (has links)
Abstract We have applied PID and IFVP techniques to modify semiconductor bandgap in quantum well and quantum dot to achieve quantum well intermixing (QWI) and quantum dot intermixing (QDI). In quantum well intermixing experiment, we combine inductively coupled plasma reactive ion etching (ICP-RIE) and sputtering 300nm SiO2 to induce defects. And then, after high temperature annealing by RTA, we observed the results by using PL measurement. The samples used in this study were grown by molecular beam epitaxy(MBE) and consists of triple In0.53Ga0.47As/In0.53Ga0.26Al0.21As quantum wells. We used Ar+ bombardment on samples by ICP-RIE for 5 minutes, and then sputtered a 300nm SiO2 capping layer upon the samples. Finally the sample was annealed at 800¢J for 1 minutes. After the process, we got 150nm blue-shift (1575~1425nm) by measurement PL spectrum and applied XRD fitting to simulate 140nm blue-shift (1580~1440nm).On the same process step, we increased ICP-RIE bombardment time to 7 minutes thus we observed largest 269nm blue-shift from PL spectrum. InAs/In0.52Al0.48As,In0.95Al0.05As/In0.52Al0.48As,and In0.95Ga0.05As/In0.52Al0.48As quantum dot structures were grown by MBE. In0.95Ga0.05As/In0.52Al0.48As quantum dot structure has larger blue-shift by sputtering 300nm SiO2 and annealing at high temperature by RTA. We got 282nm blue-shift annealing at 800¢J for In0.95Ga0.05As/In0.52Al0.48As quantum dot structure. Furthermore, we got largest 366nm blue-shift when we etched the thickness of capping layer and annealed at 800¢J.

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