Hot Carrier Thermometry in Heterostructures. Carrier Heating in Semiconductor Lasers

摘要

We consider both theoretically (intersubband lasers) and experimentally (bipolar double heterostructure laser) the physical phenomena responsible for the carrier heating effect Electron relaxation by polar excitation (LO-phonons and plasmons) was studied as a key process which determines the high-temperature operation of intersubband lasers. A simplified model for intrawell LO-phonon-assisted relaxation processes in an asymmetric one-well/one-barrier intersubband laser heterostructure was developed. A new relaxation channel for high-energy electrons by transverse plasmon-like collective excitations in intersubband laser heterostructures was predicted. It was shown that in an active quantum well with inverted subband occupation the nonequilibrium character of intersubband plasmons results in strong peculiarities of the light-emission spectra: the intersubband resonance screening of light-wave electric field leads to both narrowing and anomalous downshift of the optical gain spectrum. It was experimentally proved that suppression of the thermionic emission of electrons from the active region of bipolar MQW double heterostructure lasers leads to improvement of the device performance within a wide temperature range. We demonstrate for the first time the possibility to predict (by simulation) the 'optimum' p-i junction placement in 1.3 micrometers InGaAsP/InP MQW lasers. Such 'optimum' p-i junction placement simultaneously maximizes the external efficiency and minimizes the device threshold current.