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Absorption and Emission Properties of Light Emitting Diode Structures Containing GaInN/GaN QWs

100%

Binder J., Korona K., Borysiuk J., Wysmołek A., Baeumler M., Köhler K., Kirste L.

Acta Physica Polonica A

2011

vol. 120

issue 5

918-920

In this work we present measurements of GaInN/GaN light emitting diodes (LEDs) with an active layer consisting of three quantum wells made of Ga_{0.9}In_{0.10}N that have different widths (1.8 nm, 2.7 nm, 3.7 nm). A comparison of emission and absorption (photocurrent) on the same sample revealed a shift in energy, with the emission energy being significantly lower. The shifts are about 0.02 eV, 0.03 eV, and 0.04 eV for the quantum wells having the widths of 1.8 nm, 2.7 nm, and 3.7 nm, respectively. This can be explained by a shift of the ground state energy caused by the quantum confined Stark effect. Calculations show that due to the spontaneous polarization and the piezoelectric effect a strong electric field of the order of 1 MV/cm was present in the GaInN quantum wells. Simulations of ground-state energies in the model of an infinite square well under the influence of an electric field with a matched effective well width were performed and used to interpret the experimental results.

Electroluminescence Investigation of the Lateral Field Distribution in AlGaN/GaN HEMTs for Power Applications

68%

Baeumler M., Polyakov V., Gütle F., Dammann M., Benkhelifa F., Waltereit P., Reiner R., Müller S., Wespel M., Quay R., Mikulla M., Wagner J., Ambacher O.

Acta Physica Polonica A

2014

vol. 125

issue 4

982-985

The lifetime and stability of AlGaN/GaN heterostructure field effect transistors at high power levels can be enhanced by introducing field plates to reduce electric field peaks in the gate-drain region. Simulations of the electric field distribution along the channel using the 2D ATLAS software from Silvaco indicate that above a characteristic drain source voltage three spatially separated electric field peaks appear, one located at the drain-side edge of the gate foot, one at the end of the drain-sided gate field plate, and one at the end of the source shield field plate. The close correlation between lateral electric field and the electroluminescence due to hot electron related intra-band transitions can be very helpful when optimizing the electric field distribution in high power devices. Electroluminescence microscopy images of devices with gate and source shield field plate reveal the peaks located at the locations of enhanced electric field. By studying the voltage dependence of the electroluminescence peaks the influence of the field plates on the electric field distribution in source drain direction can be visualized.

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2 Acta Physica Polonica A

1 2014

1 2011

2 Baeumler M.

1 Ambacher O.

1 Benkhelifa F.

1 Binder J.

1 Borysiuk J.

1 Dammann M.

1 Gütle F.

1 Kirste L.

1 Korona K.

1 Köhler K.

1 Mikulla M.

1 Müller S.

1 Polyakov V.

1 Quay R.

1 Reiner R.

1 Wagner J.

1 Waltereit P.

1 Wespel M.

1 Wysmołek A.

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Absorption and Emission Properties of Light Emitting Diode Structures Containing GaInN/GaN QWs

Electroluminescence Investigation of the Lateral Field Distribution in AlGaN/GaN HEMTs for Power Applications