Laser-Thermal Impurity Pumping of Shallow Donors in Ultrapure Germanium

1989 ◽  
Vol 163 ◽  
Author(s):  
T. Theiler ◽  
F. Keilmann ◽  
E. E. Haller
Keyword(s):  
Ground State ◽  
Laser Intensity ◽  
Far Infrared ◽  
Equation Model ◽  
Degree Of Ionization ◽  
Rate Equation Model ◽  
Photothermal Ionization ◽  
Photothermal Ionization Spectroscopy ◽  
Intensity Region ◽  
Critical Intensity

AbstractExtremely narrow far-infrared lines [1] of OH-donors in ultrapure germanium are used to probe the fundamental dynamic processes of impurities. We examine the 1s-2p transition as a function of laser intensity, using photothermal ionization spectroscopy (PTIS) modified by Zeeman tuning with frequency-fixed lasers. We observe a change of the resonance line shape in the intensity region near 10-4 W/cm2. This effect can be quantitatively understood in a rate equation model which shows that at the critical intensity the ground state becomes depleted and the dependence of the recombination on the degree of ionization becomes important. Therefore the critical intensity depends also on compensation.

Far‐infrared photothermal ionization spectroscopy of semiconductors in the presence of intrinsic light

1983 ◽  
Vol 54 (6) ◽  
pp. 3464-3474 ◽  
Author(s):  
M. J. H. van de Steeg ◽  
H. W. H. M. Jongbloets ◽  
J. W. Gerritsen ◽  
P. Wyder
Keyword(s):  
Far Infrared ◽  
Photothermal Ionization ◽  
Photothermal Ionization Spectroscopy

Photothermal ionization spectroscopy of selectively boron-doped GexSi(1–x)Si strained-layer heterostructures

1989 ◽  
Vol 67 (4) ◽  
pp. 321-325 ◽  
Author(s):  
H. F. Jang ◽  
W. R. Datars ◽  
T. Timusk ◽  
A. A. Berezin ◽  
D. C. Houghton
Keyword(s):  
Dominant Role ◽  
High Mobility ◽  
Hole Mobility ◽  
Far Infrared ◽  
Experimental Conditions ◽  
Strained Layer ◽  
Boron Doped ◽  
Photothermal Ionization ◽  
Photothermal Ionization Spectroscopy ◽  
Sheet Charge

Far-infrared photothermal ionization spectroscopy has been used to investigate the impurities in selectively boron-doped GexSi(1–x)–Si strained-layer heterostructures. The spectra are obtained under various experimental conditions: with and without band-edge light and by varying the temperature of, and voltage applied to, the sample. The transport properties, resistivity, sheet charge density, and Hall hole mobility of these samples are presented. It is found that a sample with a two-dimensional hole gas (2-DHG) behavior at the GexSi(1–x)–Si interface has a weak photoresponse. This is due to a small number of photo-generated carriers in comparison with the residual hole carriers. For samples that do not show 2-DHG behavior, the photo-response from the substrate plays the dominant role for low applied voltages. At higher voltages, the response from the epitaxial layers becomes evident. The majority impurity is identified as the intentional dopant boron, and the dominant minority impurity is found to be phosphorus. It is concluded that although the free carriers are generated in the heavily B-doped layer, those carriers conducted through the low-energy high-mobility GexSi(1–x)–Si interface dominate the photoresponse.

Far-infrared spectrum and ground state constants of methyl amine

1987 ◽  
Vol 126 (2) ◽  
pp. 443-459 ◽  
Author(s):  
Nobukimi Ohashi ◽  
Kojiro Takagi ◽  
Jon T. Hougen ◽  
W.Bruce Olson ◽  
Walter J. Lafferty
Keyword(s):  
Infrared Spectrum ◽  
Ground State ◽  
Far Infrared ◽  
Methyl Amine

scholarly journals Efficiency Droop and Effective Active Volume in GaN-Based Light-Emitting Diodes Grown on Sapphire and Silicon Substrates

2019 ◽  
Vol 9 (19) ◽  
pp. 4160 ◽  
Author(s):  
Ryu ◽  
Ryu ◽  
Onwukaeme
Keyword(s):  
Quantum Well ◽  
Rate Equation ◽  
Equation Model ◽  
Efficiency Droop ◽  
Internal Electric Field ◽  
Active Volume ◽  
Light Emitting ◽  
Rate Equation Model ◽  
Sapphire Substrates ◽  
The Difference

We compared the efficiency droop of InGaN multiple-quantum-well (MQW) blue light-emitting diode (LED) structures grown on silicon(111) and c-plane sapphire substrates and analyzed the efficiency droop characteristics using the rate equation model with reduced effective active volume. The efficiency droop of the LED sample on silicon was observed to be reduced considerably compared with that of the identical LED sample on sapphire substrates. When the measured external quantum efficiency was fitted with the rate equation model, the effective active volume of the MQW on silicon was found to be ~1.45 times larger than that of the MQW on sapphire. The lower efficiency droop in the LED on silicon could be attributed to its larger effective active volume compared with the LED on sapphire. The simulation results showed that the effective active volume decreased as the internal electric fields increased, as a result of the reduced overlap of the electron and hole distribution inside the quantum well and the inhomogeneous carrier distribution in the MQWs. The difference in the internal electric field of the MQW between the LED on silicon and sapphire could be a major reason for the difference in the effective active volume, and consequently, the efficiency droop.

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