Persistent spectral-hole burning in SiC:V via excited-state absorption

Abstract

We performed persistent spectral-hole burning in the γ line of V 4+ in the wide-gap semiconductor 6H-SiC at 11 K. The hole burning was achieved by two-step photoionization of V 4+ from the 2E ground state via the 2T 2 excited state to the conduction band (“self-gated” spectral-hole burning). The spectral holes were stable up to temperatures of at least 320 K. Optical erasure of the spectral holes was possible by pumping of electrons back from stable traps as well as by a charge-transfer transition from the valence band to the V 5+ ions. In this context, typical features of spectral-hole burning in a semiconductor system are discussed. The homogeneous line width of the γ line could be determined by the hole-burning experiments to be 0.3 cm −1 yielding a coherence time of 18 ps. The temperature dependence of the hole width shows this coherence time to be essentially determined by the excited state's (remarkably short) lifetime.