Fraunhofer Institute fu r Angewandte Festkorperphysik

Freiburg, Germany

Fraunhofer Institute fu r Angewandte Festkorperphysik

Freiburg, Germany
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Galler B.,OSRAM | Lugauer H.-J.,OSRAM | Binder M.,OSRAM | Hollweck R.,OSRAM | And 6 more authors.
Applied Physics Express | Year: 2013

We investigate theoretically the influence of type and density of background carriers in the active region on the quantum efficiency of InGaN-based light emitters using an extension of the ABC rate model. A method to determine experimentally whether a certain type of Auger recombination is relevant in InGaN quantum wells is derived from these considerations. Using this approach, we show that the physical process which is the dominant cause for the efficiency droop is superlinear in the electron density and can thus be assigned to nnp-Auger recombination. © 2013 The Japan Society of Applied Physics.


Passow T.,Fraunhofer Institute fu r Angewandte Festkorperphysik | Gutt R.,Fraunhofer Institute fu r Angewandte Festkorperphysik | Kunzer M.,Fraunhofer Institute fu r Angewandte Festkorperphysik | Pletschen W.,Fraunhofer Institute fu r Angewandte Festkorperphysik | And 5 more authors.
Japanese Journal of Applied Physics | Year: 2013

High-efficiency AlGaN-based 355nm UV light-emitting diodes (LEDs) grown on low-dislocation-density AlGaN/sapphire templates with an output power of 9.8mW (22.7mW) at a DC current of 40mA (100 mA) are reported. The corresponding maximum external quantum efficiency and maximum power efficiency are 7.2 and 6.5%, respectively. Based on a rate equation model, a method is presented to derive the extraction as well as the injection and internal quantum efficiency as a function of the driving current. The thus obtained injection and internal quantum efficiencies amount to 51 and 47% at 40 mA, the extraction efficiency to 29%. © 2013 The Japan Society of Applied Physics.


Albrecht B.,Fraunhofer Institute fu r Angewandte Festkorperphysik | Kopta S.,Fraunhofer Institute fu r Angewandte Festkorperphysik | John O.,Fraunhofer Institute fu r Angewandte Festkorperphysik | Kirste L.,Fraunhofer Institute fu r Angewandte Festkorperphysik | And 4 more authors.
Japanese Journal of Applied Physics | Year: 2013

The development of AlGaN pin photodetectors sensitive in the UV range with different narrow band active regions is reported in this paper. Structures were grown by metalorganic vapor phase epitaxy on (0001) sapphire substrates using three-dimensional GaN as well as high temperature AlN nucleation. Very high specific detectivities of 1 × 1014 cm Hz0:5W-1 can be achieved based on optimized growth conditions of undoped and doped AlGaN layers with an Al-content ranging from 0% up to 100%. The crack-free AlGaN layers have edge dislocation densities in the range of 5 × 109 cm-2. Based on the two different nucleation types, pin layer structures were grown and fabricated to UV-A (320 to 365 nm) and UV-C (≤ 280 nm) photodetectors. The electro-optical performance of these photodetectors measured on-wafer will be presented in this paper, supplemented by the data of a single photodetector chip mounted in a TO 18 package. © 2013 The Japan Society of Applied Physics.

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