Date of Award

1-1997

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

Robert B. Hengehold, PhD

Abstract

Optical studies have been conducted upon CdGeAs2 and ZnGeP2, two of the most promising semiconductors being developed for mid-infrared non-linear optics applications. These experiments included photoluminescence (PL) studies of both compounds as well as photoreflectance (PR) measurements upon CdGeAs2. In addition, Hall effect measurements were carried out upon CdGeAs2, to aid in interpretation of the optical data. PL was measured as a function of laser power, sample temperature, and crystal orientation for CdGeAs2. One broad weak peak near 0.38 eV, and another somewhat narrower and often far brighter peak near 0.57 eV were found by low temperature (4 K) PL measurements. Strongly polarized PL was observed with the E field of the PL parallel to the material's c-axis. A polarization ratio as high as 6:1 was observed. PL on ZnGeP2 in the mid-IR revealed a previously unreported PL peak near 0.35 eV. PR measurements on CdGeAs2 allowed the estimation of the bandgap as a function of temperature. Hall effect measurements on CdGeAs2 reveals the dominant acceptor level lies about 120 meV above the valence band.

AFIT Designator

AFIT-DS-ENP-97-03

DTIC Accession Number

ADA339037

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