THEORETICAL STUDY OF UNIPOLAR INTERSUBBAND IMPACT IONIZATION IN QUANTUM DOT BASED PHOTODETECTORS

Abstract

In this paper, we study the intersubband impact ionization through conduction band states of quantum dot (QD) layers of an infrared photodetector. For this purpose, a photogenerated electron moving in high field active region of a p-i-n diode is assumed which can excite an electron from ground state of a QD by carrier–carrier scattering. The generated electron can escape the QD by tunneling and contribute in photocurrent giving avalanche gain to photodetector. The ionization rate and responsivity of detector are calculated from an analytical approach of intersubband transition rate equations. Results show increased responsivity in the order of several A/W.