Band gap measurement using optical absorption method

Date

3-1999

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Emmanuel A Florido

Abstract

An instrument for measuring the band gap energy of a semiconductor was designed. tested and implemented. The optical absorption method of obtaining the band gap energy was used. Two phototransistors were used as photodetectors and their response were studied based on the measured parameters transmission and absorbance. An Indium Nitride (InN) semiconductor was used as sample. It has a known experimental band gap of 1.9 eV (Florido).The absorption coefficient was computed using Beers Law I=I,,exp(-ad), where a is the absorption coefficient and d is the thickness of the sample. The photon energy was plotted against the square of the absorption coefficient and a line fit is generated from the knee of the curve . The x intercept of the fit was computed which is the band gap of the sample. Using the MRD300 phototransistor, the computed band gap averaged to 1.92 eV and about 1.87 eV using the L14G3 phototransistor . with an average percent error of 0.88 % and 1.76%, respectively.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Document Type

Thesis

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