On time delays in lead salt semiconductor diode lasers

Recently reported value of minority carrier lifetimes and time delays in lead salt diode lasers appear anomalous [A. Qadeer et al.: Appl. Phys. A33, 181–182 (1984)]. Two laser diodes, fabricated by the same technique (Hot Wall Epoxy) and of identical chemical constituents (PbSnTe and PbSnSe) failed to provide experimental evidence supporting these recently reported values, even when operated close to, but above the respective values of laser threshold current.This work was carried out at the Department of Applied Physics, Hull University, Hull (U.K.) while the author was a research student