Electrical and Optical Output Characteristics of InP/InGaAsP pnpn Structures Grown via LPE

Abstract

Gated p(1nP)-n(InP)-p(1nGaAsF’)-n(1nP) struchires have been fabricated via LPE. These devices are shown to have gate controlled, thyristor like, DC switching characteristics as well as gate controlled optical output at 940nm and 1280nm. The switching characteristics of these devices are also reported. Introduction The fabrication of PNPN devices from III-V compounds has recently received much interest due to the possibility of using these devices not only as optoelectronic power control elements [14], but also for applications such as dynamic memories [ 5 ] , two and three terminal optoelectronic switches [6,7]. optical amplifiers [SI and negative differentialresistancelasers,(NDRLaser) 191. Todate,researchinthis typeofsmcturehasbeencenteredontheGaAs/ AlGaAs matenal system, however, due to interest in optoelectronic devices operating at 1.3 and 1 . 5 5 ~ , the I@/ InGaAsP system is also receiving interest r8.101. At present, with respect to the InPDnGaAsP system, only two terminal devices have been successfully fabricated. This work presents the successful fabrication of an InPflnGaAsP based, three terminal pnpn optothynstor. The device presented here combines a double heterosmcture (DH) laser structure with a conventional thyristor into a single device. Negative differential resistance switching, with a maximum gate controlled breakover voltage of approximately 8V, is reported. An increase in the spontaneous emission of light at both 1.3 and 0 . 9 3 ~ is observed upon device switching from the high impedance OFF state to the low impedance ON state, suggesting the possibility of laser output when the device is fabricated into a suitable laser cavity. Measmments of the dynamic switching reveal device tum-on to be composed of a delay time followed by a more rapid (20011s) switching to the low impedance state. The switching delay time was also found to decrease with an increase in the gate trigger current. An anmalous feature of decrease in optical output as a function of device switching at high gate current is also reported. Device Fabrication Figure 1 shows the device smctme used for this work. The substrate was doped with Sn while the liquid phaseepitaxy (LPE) layernandp-typedopantswereTeandZnrespectively. TheInGaAsPlayerwas grown to produce spontaneous emission of light at a wavelength of 13OOnm. SIMS measurements were used to calibrate the layer t 500pm* I--54OplTl-i 9 o o p m F 920pm Cathode 58Ovmn InP 3.0pm 3.0x1017cm-3