High-performance metal-semiconductor-metal InGaN photodetectors using CaF2 as the insulator

Solar blind metal-semiconductor-metal ultraviolet photodetectors using quasi-alloy of BGaN/GaN superlattices

“…While several physical mechanisms have been proposed for the explanation of such a gain, most of the authors [1][2][3]5,[7][8][9][14][15][16] attribute the gain phenomenon to the existence of trapping states at the active layer-metal interface. In GaN-type materials, these traps are generally attributed to threading dislocations, having acceptor-like nature.…”

“…[1][2][3][4][5][6] and MgZnO alloys, [7][8][9][10][11][12][13] have been attracting more and more attention due to their huge potential for applications (missile plume warning, flame/engine control, air/ water purification, etc.). Different structures, such as photoconductive, 3,12 p-i-n, 11,13 Schottky barrier, 2,4,5,10,11 and metal-semiconductor-metal (MSM) 1,5,7,9 were used in the fabrication of these PDs. Some of them exhibit extraordinary values of the responsivity (R) corresponding to an apparent external quantum efficiency (QE) exceeding 100%, typically in the range of 2-9 Â 10 4 , 1,3,7-13 indicating large internal gains in these PDs.…”

“…To reduce the dark current, an insulation layer between the Schottky contact and active layer has been used by Sang et al 1 who proposed the use of a CaF 2 layer deposited on InGaN material. The dark current was reduced by six orders of magnitude compared with those without CaF 2 layer, with a value of the internal gain equal to 40.…”

“…In GaN-type materials, these traps are generally attributed to threading dislocations, having acceptor-like nature. 1 Under illumination, these interface states can trap photogenerated holes, thus leading to a Schottky barrier height (SBH) decrease DU b and producing a secondary photocurrent, 14 …”

Performance enhancement of GaN metal–semiconductor–metal ultraviolet photodetectors by insertion of ultrathin interfacial HfO2 layer

“…The utilization of interfacial insulating layer is an effective approach to suppress the leakage current and improve the device performance. Sang et al 12 have proposed to utilize CaF 2 as an insulation layer to reduce dark current on InGaN and succeeded to suppress dark current by 6 orders of magnitude in comparison to without CaF 2 . Lee et al 13 have suppressed dark current of GaN based UV PDs by depositing GaO x in between metal and the GaN.…”