Thickness Dependence of Electroluminescence in a-Si:H P-I-N Devices

Abstract

Electroluminescence studies in a-Si:H p-i-n devices have been made as a function of i-layer thickness (0.4 - 10 (μm), temperature (80 -300 K) and applied electric field (2xl03 – lx105 V/cm field across the i-layer). In particular, the spectral emission and lifetime distributions have been determined. With increasing temperature, there is a shift toward defect luminescence (0.9 eV) in all samples as found in photoluminescence. However, thicker samples (> 2.0 μm) show significantly more main band emission (1.2 eV) than thin samples. This trend is particularly true at higher applied voltages. Further, in thin samples, the lifetime distribution peaks at 10-6 sec in whole temperature range while in thick samples at lower temperature (< 250 K) the lifetime distribution is double peaked at 10-6 sec and at 10-3Sec.