A laboratory experiment with blue light-emitting diodes

Redondo, E.; Ojeda, A.; González-Dı́az, G.; Mártil, I.

doi:10.1119/1.18547

Cited by 8 publications

(4 citation statements)

References 5 publications

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“…For earlier student experiments with LEDs, see [14][15][16][17][18] and references therein. Here, some experiments with a blue and a green LED are presented.…”

Section: Experiments With Ledsmentioning

confidence: 99%

Nobel Prize for blue LEDs

Kraftmakher

2015

Eur. J. Phys.

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A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and 'efficiency droop' in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

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“…For earlier student experiments with LEDs, see [14][15][16][17][18] and references therein. Here, some experiments with a blue and a green LED are presented.…”

Section: Experiments With Ledsmentioning

confidence: 99%

Nobel Prize for blue LEDs

Kraftmakher

2015

Eur. J. Phys.

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“…At higher temperatures, threshold current increases to higher value and hence more current is needed to turn on the laser for a given amount of output optical power. [4], [5], [6] Experimental Set-up The automated characterization module was built using Student Version of LabVIEW 8.5.1 and its compatible Data Acquisition (DAQ) card, NI USB-6008 for interfacing. The experimental set-up and its working for the two different characteristic studies are explained as under:…”

Section: Theorymentioning

confidence: 99%

Development of an automated modern undergraduate optics laboratory using LabVIEW

2009

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We report here the development of an automated modern optics laboratory for undergraduate students. This developed modern optics laboratory have automated experiments on optoelectronic device characterisation, optical instrumentation, CCD based optical experiments and advanced applications in optics. In the device characterisation section, Voltage-Current (V-I) and Optical Power-Current (P-I) characteristics of various optoelectronic devices like LEDs, Laser diodes and photo diodes have been automated. In the optical instrumentation section, development of PC based optical power meter have been reported whose functionality can be tailored as per the need of the designed experiment. In the CCD based optical experiments section, CCD has been integrated for fringe capture and analysis by studying the diffraction pattern of a pinhole. In the advanced applications in optics section, molar absorbivity of NiSO 4 has been calculated. Further work is in progress to develop heart rate monitoring system, non-evasive jaundice studies from the skin, CCD based real time spectrometers as well as elaborate studies on interference, diffraction and polarisation. The automation of this laboratory has been done by integrating various sensors (photodetectors, CCDs, Current and others) with data acquisition cards connected to PC and one of the most widely used world wide scientific graphical programming software LabVIEW. The purpose of the laboratory is to invoke student interest by exposing them to various modern tools in comparison to very conventional as well as boring existing optics laboratories. The use of this scientific graphical programming software will help in performing various real time measurements and calculations with ease. The automation of the experiments will also save great amount of experimentation time and procurement of costly equipments dedicated to each experiment thus providing an efficient way to carry out studies with reduced financial constraints and better manoeuvrability.

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“…For example, electrical measurements on forward-biased diodes and Hall devices have been used to measure the semiconducting band gap, [1][2][3][4][5][6] Schottky barrier height, 7 charge carrier density, [8][9][10] carrier transport properties, 11,12 and carrier statistical distributions. 13 Additionally, optical experiments are available to determine the band gap of bulk, 14,15 thin film, 16 and quantum-dot 17 semiconductor samples, the Maxwell-Boltzmann distribution of charge carriers, 18 and the vibration properties of nanomaterials. 19 In this paper, we describe a newly developed instructional lab experiment that implements capacitance-voltage (CV) profiling on a reverse-biased Schottky barrier diode to determine the density of impurity dopants in its semiconductor layer, as well as its built-in electric potential.…”

Section: Introductionmentioning

confidence: 99%

Capacitance-voltage profiling: Research-grade approach versus low-cost alternatives

Reynolds

Panda

Essick

2014

American Journal of Physics

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We describe an experiment that implements capacitance-voltage profiling on a reverse-biased Schottky barrier diode to determine the density of impurity dopants in its semiconductor layer as well as its built-in electric potential. Our sample is a commercially produced Schottky diode. Three different experimental setups, one using research-grade instrumentation, the other two using low-cost alternatives, are given and their results compared. In each of the low-cost setups, phase-sensitive detection required to measure the sample's capacitance is carried out using an inexpensive data acquisition (DAQ) device and a software program that implements a lock-in detection algorithm. The limitations of the DAQ device being used (e.g., restricted analog-to-digital conversion speed, inadequate waveform generation capabilities, lack of hardware triggering) are taken into account in each setup. Excellent agreement for the value of the doping density obtained by the all three setups is found and this value is shown to be consistent with the result of an independent method (secondary ion mass spectroscopy). V

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A laboratory experiment with blue light-emitting diodes

Cited by 8 publications

References 5 publications

Nobel Prize for blue LEDs

Nobel Prize for blue LEDs

Development of an automated modern undergraduate optics laboratory using LabVIEW

Capacitance-voltage profiling: Research-grade approach versus low-cost alternatives

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