Zn(MgBe)Se ultraviolet photodetectors

We present the growth and characterization of blue-violet and ultraviolet p hotodetectors based on ZnSe and Zn(Mg)BeSe compounds. Structures are grown by molecular beam epitaxy on (001) GaAs substrates. Three types of photodet ectors have been fabricated. Zn(Mg)BeSe p-i-n photodiodes exhibit a high re sponse of 0.17 A/W with a rejection rate of 10(4) and a wavelength cutoff o f 450 nm. Schottky barrier photodiodes based on planar geometry devices dis play a very flat response above the band gap with a rejection rate above 10 (3). High responses with quantum efficiency higher than 50% have been obtai ned. The wavelength cutoff can be tuned from 460 (ZnSe) to 380 nm (ZnMgBeSe ), which leads to visible blind devices. Detectivities from 2.0 x 10(10) (Z nMgBeSe) to 1.3 x 10(10) mHz(1/2)W(-1) (ZnSe) have also been measured. Meta l-semiconductor-metal devices, recently fabricated, exhibit a spectral resp onse very similar to Schottky devices. Quantum efficiencies of 40% are easi ly obtained in these devices with a rejection rate of 10(3).