Photoluminescence studies of InGaAs/AlGaAs multiple quantum wells under high pressure

Using diamond anvil cells, the photoluminescence spectra of InGaAs/AlGaAs MQW (multiple quantum wells) with well widths from 1.7 to 11.0 nm were measured at 77K under high pressure up to 4 GPa. Experimental results show that the pressure coefficients of the exciton peaks corresponding to transitions from the first conduction subband to the heavy-hole subband decrease with increasing well width for In0.15Ga0.85As/GaAs MQW. However, the corresponding pressure coefficients increase for In0.15Ga0.85As/Al0.33Ga0.67As and GaAs/Al0.33Ga0.67As MQW, respectively. Calculations based on the Kronig-Penney model reveal that the increased or decreased conduction-band off-sets and the increased effective masses of electrons with increasing pressure are the main reasons for the change in the pressure coefficients.