Accession Number:

ADA434205

Title:

Limitations in Time Resolved Photoluminescence of Gallium Nitride Using a Streak Camera

Descriptive Note:

Master's thesis Jun 2004-Mar 2005

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT

Personal Author(s):

Report Date:

2005-03-01

Pagination or Media Count:

102.0

Abstract:

Semiconductor performance is often characterized in terms of the rate at which its carrier recombination processes occur. Carrier recombination, including radiative, and Shockley-Read-Hall and Auger both nonradiative, occurs at ultra-fast times in the picosecond or femtosecond regimes. A device which can measure both spectral data and temporal phenomena at this speed is the streak camera. The capability to do time-resolved spectroscopy of wide band gap semiconductors using a streak camera has been established at AFIT for the first time. TRPL from samples of gallium nitride were measured at temperatures of 5 K over spectral bands of 36.6 and temporal ranges of 45 to 1970 ps, both instrument-limited. TRPL features at 3552 and 3587 were studied giving decay lifetimes of 43.2 1.6 ps and 16.8 3.4 ps, respectively. Shockley-Read-Hall, Radiative and Auger coefficients were found but parameterized in terms of experimental efficiency, n, which was not measured. These values, determined using a least-squares-error fit of the carrier recombination rate equation to collected data, are -9.3109 4.9108 s-1, 7.51017 n 8.01016 n cm3s, and 1.81025 n2 2.91024 n2 cm 6s respectively, for the first peak and -2.5 1010 5.2109 s-1, 4.91019 n 2.01019 n cm3s and -1.41028 n2 8.61027 n2 cm6s for the second peak. Since alignment of the streak camera has not yet been optimized, large but unquantified uncertainty in these results exists. Isolating vibrations and improving streak camera alignment should reduce the uncertainty and permit data collection temporally resolved at hundreds of femtoseconds.

Subject Categories:

  • Photography
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE