Silicon quantum cascade lasers for THz sources

Abstract

Abstract-This paper covers some recent advances in the search for a silicon quantum cascade laser. These include intersubband lifetime measurements, growth of high quality structures on buried silicide layers, and demonstration of THz electroluminescence.

Silicon photonics: a bright future?

“…Terahertz technology has the possibility of opening a whole new range of applications, including high bandwidth telecoms [12], hyperspectral imaging for chemical identification, security imaging, oncology (skin cancer imaging), production monitoring and drug discovery [13,14]. While III -V QCLs have been limited to low temperature operation [12], Si/SiGe QCLs have the enormous advantage that they should operate at higher temperatures owing to the lack of polar optical phonon scattering [13,15]. Experimental measurements [13,15] demonstrate the weak temperature dependence of the non-radiative lifetimes up to 225 K, which is in stark constrast to the strong decrease in lifetimes in III-V materials as the temperature is increased above 40 K.…”

“…While III -V QCLs have been limited to low temperature operation [12], Si/SiGe QCLs have the enormous advantage that they should operate at higher temperatures owing to the lack of polar optical phonon scattering [13,15]. Experimental measurements [13,15] demonstrate the weak temperature dependence of the non-radiative lifetimes up to 225 K, which is in stark constrast to the strong decrease in lifetimes in III-V materials as the temperature is increased above 40 K.…”

“…Most of the Si-based QCL work to date has concentrated on p-type Si 1-x Ge x with relatively low Ge concentrations ( 0.5) [13,14], but the gain has been severely limited by the high effective mass of . 0.3 m 0 , where m 0 is the free electron mass (Fig.…”