Experimental determination of the effective minority carrier lifetime in the operation of a quantum-well $n-p-n$ heterojunction bipolar light-emitting transistor of varying base quantum-well design and doping

The authors show that the electrical characteristics of an $n-p-n$ transistor structure can be used to determine experimentally, under dynamical operating conditions, the effective carrier lifetime of injected minority carriers in the quantum-well (QW) base region of a heterojunction bipolar light-emitting transistor. The carrier lifetime is progressively reduced from $134ps$ (no base QW) to $∼35ps$ by inserting single or double QWs of increasing width to enhance the effective capture cross section for injected carriers (electrons), and is further reduced to $∼10ps$ by increasing the $p$-type doping from $5×1018to4×1019cm−3$⁠.