scholarly journals Pressure Dependence of Optical Transitions in InGaN/GaN Multiple Quantum Wells

1999 ◽  
Vol 4 (S1) ◽  
pp. 191-196
Author(s):  
W. Shan ◽  
J.W. Ager ◽  
W. Walukiewicz ◽  
E.E. Haller ◽  
M.D. McCluskey ◽  
...  

The effect of hydrostatic pressure on optical transitions in InGaN/GaN multiple quantum wells (MQWs) has been studied. Photoluminescence (PL) and photomodulated transmission (PT) measurements were performed under applied pressure to examine the pressure dependence of optical transitions associated with confined states in MQWs. The PL emission from the MQWs was found to shift linearly to higher energy with applied pressure but exhibit a significantly weaker pressure dependence compared to epilayer samples with similar bandgap energies. Similar pressure coefficients obtained by PT measurements rule out the possibility of PL resulting from deep localized states. We show that the difference in the compressibility of InGaN and of GaN induces a tensile strain in the compressively strained InGaN well layers that partially compensates the applied hydrostatic pressure. This mechanical effect is the primary factor for the smaller pressure dependence of the optical transitions in the InGaN/GaN MQWs. At pressure above 100 kbar, the PL signal in MQWs samples is quenched, indicating that the carriers involved in the radiative recombination processes in the well layers originate primarily from the adjacent GaN layers.

1998 ◽  
Vol 537 ◽  
Author(s):  
W. Shan ◽  
J.W. Ager ◽  
W. Walukiewicz ◽  
E.E. Haller ◽  
M.D. McCluskey ◽  
...  

AbstractThe effect of hydrostatic pressure on optical transitions in InGaN/GaN multiple quantum wells (MQWs) has been studied. Photoluminescence (PL) and photomodulated transmission (PT) measurements were performed under applied pressure to examine the pressure dependence of optical transitions associated with confined states in MQWs. The PL emission from the MQWs was found to shift linearly to higher energy with applied pressure but exhibit a significantly weaker pressure dependence compared to epilayer samples with similar bandgap energies. Similar pressure coefficients obtained by PT measurements rule out the possibility of PL resulting from deep localized states. We show that the difference in the compressibility of InGaN and of GaN induces a tensile strain in the compressively strained InGaN well layers that partially compensates the applied hydrostatic pressure. This mechanical effect is the primary factor for the smaller pressure dependence of the optical transitions in the InGaN/GaN MQWs. At pressure above 100 kbar, the PL signal in MQWs samples is quenched, indicating that the carriers involved in the radiative recombination processes in the well layers originate primarily from the adjacent GaN layers.


1990 ◽  
Vol 04 (14) ◽  
pp. 917-920 ◽  
Author(s):  
Y. FU

The temperature and hydrostatic pressure dependence of GaAs/AlxGa1−xAs multiple quantum well subband structures has been examined theoretically. Such effects on the subband energy measured from the corresponding band optimum are negligible, and therefore, the temperature and the hydrostatic pressure coefficients of these multiple quantum wells are dominated by those coefficients of the bulk GaAs bandgap.


1996 ◽  
Vol 449 ◽  
Author(s):  
M. Smith ◽  
J. Y. Lin ◽  
H. X. Jiang ◽  
A. Khan ◽  
Q. Chen ◽  
...  

ABSTRACTTime-resolved photoluminescence (PL) has been employed to study the optical transitions and their dynamical processes in GaN and InxGa1-xN epilayers, and GaN/GaN and GaN/ALxGa1-xN multiple quantum wells (MQW). We compare the results from both metal-organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) grown samples. In addition, results are also compared with GaAs/ALxGa1-xAs MQW. It was found for all samples that the low temperature emission lines were dominated by radiative recombination transitions of either localized or free excitons, which demonstrates the high quality and purity of these III-nitride materials.


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