Energy Band Gap Apparatus

Product Code : SCL-EAE-11181

Specifications

How the energy band gap experiment is done

In a reverse-biased PN junction only a tiny saturation current flows, carried by minority carriers created when thermal energy lifts electrons across the forbidden gap. The number of such carriers, and so the reverse current, rises very steeply with temperature, approximately as exp(-Eg/kT), where Eg is the band gap and k is Boltzmann's constant. Measuring the reverse current at several temperatures therefore reveals Eg.

1. Place the diode probe and thermometer in the oven and connect the diode in reverse bias to the console.
2. Switch on the supply and note the reverse current at room temperature.
3. Switch on the oven and let the temperature rise to the upper end of the working range, then switch the heater off.
4. As the diode cools, record the reverse current every few degrees.
5. Plot log10 Is against 10^3/T, with T in kelvin, and measure the slope of the straight line.

The band gap follows from the slope: Eg = 0.198 x slope, in electronvolts, when common logarithms are used. Values near 0.7 eV point to germanium and near 1.1 eV to silicon, a useful check on the result.

Key features

• Built-in digital voltmeter and micro-ammeter for clear readings of small reverse currents.
• Regulated DC supply that holds the reverse bias steady during a run.
• Miniature electric oven with a thermometer slot for controlled heating of the diode.
• Encapsulated diode probe for safe handling at raised temperatures.
• Insulated safety terminals and fused circuitry.
• Powder-coated steel console for regular laboratory use.

What is included

• Main console
• Miniature electric heating oven assembly
• Encapsulated semiconductor diode probe
• Glass thermometer, 0-110 deg C
• Set of insulated patch cords
• Experiment manual with calculation formulae

Documentation and supply

An experiment manual with calculation formulae is supplied with the apparatus. Most Lab Exports products carry a one-year manufacturer warranty.

Lab Exports manufactures the energy band gap apparatus at its works in Laxmi Nagar, Delhi, and supplies it to colleges and universities in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.

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The full range is in the Electrical and Electronics section of the Physics Lab range.

Frequently asked questions

How is the band gap calculated with this apparatus?

The reverse saturation current is measured at several temperatures and log10 Is is plotted against 10^3/T. The band gap is Eg = 0.198 x slope, in electronvolts.

Why is the diode reverse biased in the band gap experiment?

The reverse saturation current comes from thermally generated minority carriers, so its change with temperature depends directly on the energy band gap of the semiconductor.

What is the price of the energy band gap apparatus?

Prices are not published on the website. Add the energy band gap apparatus to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code SCL-EAE-11181 and the quantity, to receive a quotation.

Does Lab Exports manufacture the energy band gap apparatus?

Yes. Lab Exports manufactures the energy band gap apparatus at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code SCL-EAE-11181.

Request a quote

Email [email protected] with the house code SCL-EAE-11181 and the quantity, or add the energy band gap apparatus to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.