Measurements of the absolute external luminescence quantum efficiency in ZnSe/ZnMgSSe multiple quantum wells as a function of temperature

1998 ◽  
Vol 84 (12) ◽  
pp. 6871-6876 ◽  
Author(s):  
R. Westphäling ◽  
P. Ullrich ◽  
J. Hoffmann ◽  
H. Kalt ◽  
C. Klingshirn ◽  
...  
Author(s):  
A. E. Yunovich ◽  
V. E. Kudryashov ◽  
A. N. Turkin ◽  
A. Kovalev ◽  
F. Manyakhin

Luminescence spectra of Light Emitting Diodes (LEDs) with Multiple Quantum Wells (MQWs) were studied at currents J = 0.15 μA - 150 mA. A high quantum efficiency at low J is caused by a low probability of the tunnel current J (which is maximum at Jm ≈ 0.5-1.0 mA). J(V) curves were measured in the range J= 10−12-10−1 A; at J > 10−3A they may be approximated by a sum of four parts: V= φk+ mkT·[ln(J/J0)+(J/J1)0.5] + J·Rs. The part V ~ (J/J1)0.5is the evidence of a double-injection into i-layers near MQWs. Their presence is confirmed by capacitance measurements. An overflow of carriers through the MQW causes a lower quantum efficiency at high J. A model of a 2D-density of states with exponential tails fits the spectra. The value of T in the active layer was estimated. A new band was detected at high J; it can be caused by non-uniformity of In content in MQWs.


2019 ◽  
Vol 7 (22) ◽  
pp. 6534-6538 ◽  
Author(s):  
Shanshan Chen ◽  
Chenxiao Xu ◽  
Xinhua Pan ◽  
Haiping He ◽  
Jingyun Huang ◽  
...  

Dramatically reduced edge threading dislocations and a record IQE of 61% are obtained for ZnO/Zn0.9Mg0.1O MQWs by using GaN/Al2O3 as substrates.


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