Infrared emitting HgTe quantum dots and their waveguide and optoelectronic devices

Abstract

The development of the research into the synthesis and optoelectronic applications of HgTe and related quantum dots (QDs) is reviewed, from the early days when it was felt that it might be a useful replacement for rare earths in telecom optical amplifiers, through to its more recent and broader appeal as an IR photodetector technology. Appropriately the early investigation of the material sprang from a contact with Prof. Horst Weller and his group at Hamburg University. Though the problem of Auger recombination meant that it was not so easy to make telecom amplifiers and lasers as many had hoped, it has proved to have an extraordinarily broad bandgap tuning range and just recently this has resulted in the demonstration of photodetectors in the mid-to long-IR region operating at up to 12μm wavelength. This impressive flexibility has led to interest in HgTe QDs and optoelectronic devices based on them to be as strong as ever and growing as the prospects for commercialization improve with every narrowing in the gap between the performance of present day epitaxial devices and QD-based technology. In a further satisfying and well timed twist, Prof. Weller's 60th year has seen preliminary reports of extended gain lifetime in 'doped' HgTe QDs which may yet lead to a completing of the circle with the distinct possibility of electrically driven telecom wavelength lasers and amplifiers in the coming years. This review follows the development of the several synthetic methods to grow colloidal HgTe QDs, and their deployment in optoelectronic devices to the present.